Using Frame Relay
This document describes the OpenROUTE Networks implementation of Frame Relay and how to configure it. It includes the following sections:
Frame Relay Overview
Frame Relay Manager (FRMGR)
Frame Relay LAN Emulation (FRLANE)
Frame Relay Virtual Circuit (FRVC)
Choosing Between FRLANE and FRVC
Frame Relay over ISDN
Displaying the Frame Relay Prompts
Configuring Frame Relay
FRMGR Commands
FRLANE Commands
FRVC Commands
Frame Relay Overview
Frame Relay (FR) lets you connect multiple LANs to a single high-speed WAN link using point-to-point virtual circuits. A virtual circuit is a logical connection between two sites. The FR network provides a number of virtual circuits that connect stations attached to the same Frame Relay network.
A Frame Relay network consists of the FR backbone, made up of FR switches, that provides the service. Typically, a public Frame Relay supplier offers the Frame Relay service. The router acts as the device that connects your LANs to the Frame Relay WAN.
Terminology
This document uses the following terminology.
Frame Relay Services
Like other OpenROUTE Networks WAN implementations, Frame Relay consists of a physical device and logical interfaces. Logical interfaces run over the physical device, and you can have multiple logical interfaces running over one physical device. In addition, multiple Frame Relay VCs can run over each logical interface.
The OpenROUTE Frame Relay software provides a set of services made up of the following:
You can set up multiple FRLANE interfaces and FRVC interfaces, or a combination of the two types of interfaces on each physical Frame Relay device. The FRMGR configuration applies to all logical interfaces on the device. Figure 1 shows a Frame Relay device that has two FRLANE interfaces and one FRVC interface.
Figure 1 Frame Relay Device With Two FRLANE Interfaces and One FRVC Interface
Frame Relay Features
Frame Relay provides the following features:
- High throughput and low delay. Using the core aspects (error detection, addressing, and synchronization) of the Link Access Protocol, D-channel (LAPD) datalink protocol, FR eliminates all network layer (Layer 3) processing. By using only the core aspects, FR reduces the delay of processing each frame.
- LAN Emulation. Using FRLANE, you can group many circuits onto one interface. FRLANE features include static or dynamic address mapping, multicast emulation, and protocol broadcast.
- Single Virtual Circuit Mode. Using FRVC, the VC acts as a point-to-point connection to protocols that run over the VC.
- PPP over FRVC. Frame Relay Virtual Circuits can send PPP traffic over the circuit using PPP over Frame Relay encapsulation specified in RFC 1973. Using this feature along with PPP data compression gives you a method of compressing data sent over the circuit.
- Network management. As your network requires, Frame Relay can operate with or without a Local Management Interface (LMI).
- Circuit access and control. As the router dynamically learns about nonconfigured circuits (orphan circuits), you can control access to those new circuits.
- Congestion detection and control. Upon receiving Backward Explicit Congestion Notification (BECN), the router initiates a controlled slowdown of traffic, thereby avoiding a complete FR network shutdown.
- 1490 Encapsulation. The router encapsulates protocol packets as specified in RFC 1490.
- Multiplexing Virtual Circuits. Frame Relay can pass multiple protocols over one circuit. OpenROUTE supports IP, IPX, AppleTalk, and bridging.
- Statistics. Frame Relay monitoring commands provide current statistics on circuits and LMI exchanges.
FR provides no error correction or retransmission function. To provide error free end-to-end transmission of data, FR relies on the intelligence of the host devices and applications.
How Frame Relay Works
Frame Relay routes traffic based on a Data Link Connection Identifier (DLCI). The DLCI allows devices to identify a frame as being from a particular virtual circuit. The DLCI enables multiplexing of several virtual circuits over one physical link.
For example, in Figure 2, a packet destined to go from router B to router C has a DLCI of 19; however, a packet destined to go from router C to router B has a DLCI of 16.
Figure 2 DLCIs in Frame Relay Network
You can configure static circuits and/or use dynamic circuits that FR management learns about from the FR network.
A Frame Relay network has the following characteristics:
Frame Relay Frame
A Frame Relay frame consists of a fixed size control field with variable sized encapsulated user data. Figure 3 illustrates an LAPD frame format.
Figure 3 LAPD Frame Format
Table 1 describes each of the fields in an LAPD frame.
Frame Relay Manager (FRMGR)
The FRMGR configuration applies to all logical interfaces that run over the physical Frame Relay device. FRMGR handles the following Frame Relay management tasks, which are described in the next sections.
Managing the Frame Relay Network Using LMI
The supplier of the FR network backbone provides network management, which provides status and configuration information about virtual circuits.
This Frame Relay implementation supports the Local Management Interface (LMI) entities LMI Revision 1, ANSI Annex D, and CCITT Annex A. LMI notifies FRMGR of the following:
It is not necessary to use LMI for the router to operate over the FR backbone. For example, you can disable LMI during Frame Relay testing. However, you would need to configure PVCs in that case.
PVC Status
FRMGR uses LMI to interact with the Frame Relay switch to find out the status of PVCs. PVCs are either active or inactive. An active circuit has a completed connection to an end system. An inactive circuit does not have a completed connection to an end system because either an end system or an FR switch is offline.
The Frame Relay device cannot send or receive data until an LMI full status message reports the PVC as active.
For example, in Figure 4 router B has a configured PVC to router C. Router B is successfully interacting with FR management through FR switch B. Because either another FR switch is down or the end system is down, the end-to-end PVC connection is not established. Router B receives an inactive status for that PVC.
Figure 4 DLCIs in Frame Relay Network
Orphan Circuits
An orphan circuit is a virtual circuit that is not configured, but that FRMGR dynamically learns through LMI. For example, in Figure 5 router B has a configured PVC to router C, but none to router A. Router A configures a PVC to router B. Router B then learns about the PVC to router A and classifies it as an orphan.
Figure 5 Orphan Circuit
The Inverse ARP protocol for Frame Relay maps the orphan circuit DLCI (a hardware address) to a protocol address. To do this, the router sends an Inverse ARP request over the orphan circuit to the end node router (Router A in Figure 5), which returns a protocol address.
The router treats orphan circuits the same as configured circuits, except that you can enable or disable them. Enabling orphan circuits allows the router to forward packets over circuits you did not configure. Disabling orphan circuits adds a measure of security to your network by preventing unauthorized entry into your network from a nonconfigured circuit.
Management Status Reporting
Upon request, LMI provides two types of status reports, a full status report and a link integrity verification report. The next sections describe these reports. FR sends status enquiries and responses over DLCI 0 for ANSI Annex D and CCITT or DLCI 1023 for LMI Rev 1.
Enter list lmi at the FRMGR <WAN> prompt to see current status information.
Full Status Report
When FRMGR requires a full status report, it sends a status enquiry to management requesting a full status report. LMI responds with a full status report consisting of the link integrity verification element and the status of all PVCs on the device. (The next section describes the link integrity verification element.)
The PVC status contains the following information: the local DLCI number for the PVC; the state of the PVC (active or inactive); and whether the PVC is new or an existing PVC that management already knows about. Note:
The number of PVCs that LMI supplies to the FR device is restricted by the network frame size and the amount of individual PVC information elements that can fit into a full status report. For example, 202 is the maximum number of PVCs for a network with a 1K frame size.
Link Integrity Verification Report
A link integrity verification report, also called heartbeat polling, verifies the connection between an end station, in this case the router, and a Frame Relay switch. To do so, management and the router exchange send and receive sequence numbers.
The send sequence number is the current send sequence number of the message originator. The receiver looks at this number and compares it to the last send sequence number to verify that the number is incrementally correct.
The receive sequence number is the last send sequence number that the originator sent over the interface. It is the receiver's responsibility to place a copy of the send sequence number into the receive sequence number field. This way the originator ensures that the receiver receives and interprets the frames correctly.
If an end station fails to participate in this polling process, management's full status report notifies all remote end stations with logically attached PVCs.
Managing Errors
You can set a threshold for the number of management events that can contain errors during an event window. If the number of errors exceed this threshold, Frame Relay disconnects the link.
The n2-parameter sets the error threshold. The n3-parameter sets the event window. For example:
FRMGR Config <WAN> set n2-parameter
Parameter N2 [3]?
FRMGR Config <WAN> set n3-parameter
Parameter N3 [4]?
This sets an error threshold of 3 (n2 = 3) and a window size of 4 (n3 = 4), which causes the software to check four management events to determine if any are in error. If the number of events in error equals three (the n2 parameter) or more, the Frame Relay device considers the network to be Down and resets.
For the Frame Relay device to consider the network to be Up, the number of events in error within the window must be less than n2 prior to any change in status.
Defining Data Rates
Your Frame Relay service provider can tell you the correct value for each data rate. You can use the defaults or define these rates with the add permanent-virtual-circuit FRMGR command. The router does not negotiate these rates with the Frame Relay switch.
Committed Information Rate (CIR)
CIR is the data rate that the FR service provider commits to support for both PVCs and orphan circuits under normal, uncongested conditions. The CIR is a portion of the total throughput for the physical link between 300 bits per second (bps) and 1.54 Megabits per second (Mbps). The most common CIR, and the default CIR, is 64 Kilobits per second (Kbps).
Orphan Circuit CIR
The router assigns orphan circuits a CIR of 64 Kbps. If you rely on an orphan circuit to route important data, you should add a PVC in place of the orphan. Doing so lets you assign a CIR that the network commits to support.
Committed Burst (Bc) Size
Bc is the maximum amount of data in bits that the network commits to deliver during a calculated time (Tc) interval. To calculate the Tc, divide the Bc by the CIR.
Bc/CIR = Tc
For example, if a VC's CIR is 9600 bps, and the Bc is 14,400 bits, the Tc is 1.5 seconds (14,400/9600 = 1.5 seconds). This allows the VC to transmit a maximum of 14,400 bits in 1.5 seconds.
The Bc is important because of its relationship to the maximum frame size. If the maximum frame size in bits is greater than the Bc, the network may discard frames whose size exceeds the Bc. Therefore, make sure the Bc is greater than or equal to the maximum frame size.
The default Bc is 64000 bits.
Excess Burst (Be) Size
Be is the maximum amount of uncommitted data the router can transmit on a VC in excess of the Bc during the time interval Tc (Bc/CIR=Tc).
The network delivers this excess data with a lower probability of success than committed burst size data. Set the Be greater than zero only if you are willing to accept the risk of discarded data and its effect on higher-layer protocol performance.
The default Be is 0.
Minimum and Maximum Information Rates (IR)
The minimum IR is the minimum amount of data the router sends over a VC in time interval Tc (Tc=Bc/CIR) during periods of network congestion. Set the minimum IR using the set ir-adjustment command.
The maximum IR is the maximum amount of data the router sends.
You do not set the maximum IR; the router calculates the maximum IR using the CIR, Bc, and Be as follows:
(Bc + Be) / Tc = maximum IR
Variable Information Rate (VIR)
The VIR ranges from the minimum IR to the maximum IR.
To avoid impulse loading of the network, the router initially sets the VIR to CIR when the network starts up.
The VIR can actually exceed the maximum IR in one case. If the length of a frame in bits is greater than the maximum IR, Frame Relay transmits the frame anyway.
Responding to Circuit Congestion
When circuit congestion occurs, the network must drop packets and/or shut down. In response to circuit congestion, the router implements a throttle down, which is a stepwise slowing of packet transmission to the configured minimum IR. Throttle down occurs during the following conditions:
This section discusses monitoring of Frame Relay data rates and how the router responds to circuit congestion.
CIR Monitoring
CIR monitoring prevents the information rate (IR) of each VC from exceeding its maximum IR.
CIR monitoring is disabled by default. To enable it, enter the enable cir-monitor command. CIR monitoring, when enabled, overrides congestion monitoring.
Congestion Monitoring
Congestion monitoring allows the VIR to vary in response to network congestion. The VIR assumes values between the minimum IR and a maximum of line speed. Congestion monitoring is enabled by default. You can disable it with the disable congestion-monitor command.
CIR monitoring, if enabled, overrides congestion monitoring. If both CIR monitoring and congestion monitoring are disabled, the VIR for each VC on the device is set to the line speed and does not change in response to network congestion.
Congestion Notification and Avoidance
Frame Relay frames contain two bits that notify the device sending or receiving frames if there is congestion on the network. The two bits are
When the router receives a BECN, it begins to throttle down the VC's IR if either CIR monitoring or congestion monitoring is enabled. As the router receives consecutive frames with BECN, it gradually throttles down until it either reaches the minimum IR, or it receives a frame without BECN. As the router receives consecutive frames without BECN, it gradually increases the IR to its maximum value.
Use the set ir-adjustment command to set the minimum IR and the percentages for increasing and decreasing the IR in response to network congestion.
Figure 6 shows a congestion condition at switch B. Management notifies the downstream node (switch C) and the end station (router) that congestion is occurring by setting the FECN bit on all outgoing frames. Management must also notify switch A and the other end station that congestion is occurring by setting the BECN bit.
Figure 6 Congestion Notification and Throttle Down
Note:
If multiple VCs are configured between two end stations when congestion occurs, the router may use a second VC to send data until the congestion on the first VC clears.
Frame Relay LAN Emulation (FRLANE)
The LAN Emulation feature causes a Frame Relay interface to look like an Ethernet or Token Ring interface to protocols such as IP. Using FRLANE, the router encapsulates packets into FR frames and routes them through the network. FRLANE complies with RFC 1490 encapsulation, and supports IP, IPX, AppleTalk, and bridging traffic.
You can set up multiple FRLANE interfaces on each physical Frame Relay device. Each FRLANE interface can have a different protocol address and can belong to a different network. Routing protocols, such as RIP or OSPF, treat each FRLANE interface as a separate network. These features let you set up FRLANE interfaces that represent your network address structure, giving you better control of your network.
Address Mapping
When FRLANE receives a packet, it knows which virtual circuit to send the packet to by mapping the packet's protocol address to a DLCI.
You can either statically map protocol addresses to PVCs, or Frame Relay can learn them dynamically through the Inverse Address Resolution Protocol (ARP). Static address mapping can reduce broadcast traffic. In either case, Frame Relay performs this mapping by comparing the packet's protocol address to the entries in its ARP cache. If the ARP cache
Multicast Emulation
Multicast emulation allows protocols requiring multicast to work properly over the FRLANE interface. Protocols that use multicast are IP, IPX, and ARP. Multicast emulation transmits a frame on each active virtual circuit. You can turn this feature on or off using the enable and disable multicast FRLANE commands.
Protocol Broadcast
Protocol broadcast allows protocols such as RIP to function over the FRLANE interface. The multicast parameter must be enabled for protocol broadcast to function properly. You can turn this feature on or off using the enable and disable protocol-broadcast FRLANE commands.
LAN Emulation Groups
LAN emulation groups allow an FRLANE interface to use only the VCs you configured for that FRLANE interface and not circuits that it learns about from FRMGR.
You may want to enable LAN emulation groups in either of the following situations:
Use the disable and enable lane-group FRLANE configuration commands.
Frame Relay Virtual Circuit (FRVC)
FRVC interfaces use a point-to-point connection over a single VC. You can have multiple FRVC interfaces on each physical Frame Relay device. Each FRVC has one VC. You can use FRVC interfaces over orphan circuits.
The router encapsulates IP, IPX, AppleTalk, and bridging packets using RFC 1490 encapsulation and then routes them over the FRVC interface.
You can also send PPP data over an FRVC. Using this feature along with PPP data compression gives you a method of sending compressed data over an FRVC. The router uses PPP over Frame Relay encapsulation specified in RFC 1973.
With FRVC, the VC acts as a point-to-point connection to protocols that run over the VC. For example, if you are using IP, you can run RIP or use static routes over the VC. You can also assign a different IP address to each FRVC interface, which allows you to set up separate IP filters for each FRVC.
FRVC responds to Inverse ARP requests that it receives.
Choosing Between FRLANE and FRVC
Consider the following when deciding whether to use FRLANE or FRVC.
FRVC
FRVC is the default configuration for Frame Relay devices. FRVC uses one VC for each FRVC interface, and it is simpler to set up than FRLANE.
FRVC causes a VC to act as a point-to-point connection to protocols. If you use FRVC, you can
FRLANE
Usually, you would use FRLANE if the other end of the link uses FRLANE.
You can use FRLANE to group many circuits on one Frame Relay device, which lets you use only one IP address for all circuits in a group.
Each FRLANE interface can have a different IP address and can belong to a different network. Therefore, you can set up FRLANE virtual interfaces to represent your network address structure, giving you better control of your network.
Frame Relay over ISDN
Figure 7 shows how you can use ISDN to connect to a Frame Relay switch.
Figure 7 Frame Relay Over ISDN Configuration
Because of the costs involved, Frame Relay over ISDN is usually not suitable for continuous connections.
Keep the following in mind if you are using Frame Relay over IDSN:
Displaying the Frame Relay Prompts
This section shows how to display the FRMGR, FRLANE, and FRVC prompts.
Displaying the FRMGR Prompts
Note:
The FRMGR configuration applies to all interfaces on a physical Frame Relay device. If you have multiple interfaces on one device, it does not matter which Circuit Config <NET-#> prompt for the device you use to get to the FRMGR prompt.
To display the FR Manager configuration prompt (FRMGR Config <WAN>),
- 1. At the Config> prompt, enter list interfaces to see a list of interfaces configured on the router.
- 2. Set the data-link protocol for an interface to Frame Relay if it is not already Frame Relay.
Config>set data-link frame-relay
Interface Number [0]? 1
- 3. Enter the network command to display the circuit configuration prompt. The network number is the number of a Frame Relay interface.
Config>network
What is the network number [0]? 1
Circuit Configuration
Circuit Config <NET-1>
- 4. Enter frmgr.
Circuit Config <NET-1> frmgr
Frame Relay Manager Configuration
FRMGR Config <WAN>
To display the FR Manager monitoring prompt (FRMGR <WAN>),
- 1. At the monitoring prompt (+), enter list interfaces to see a list of interfaces configured on the router. Enter network followed by the number of the Frame Relay interface that you want to monitor.
+network 1
Circuit <NET-1>
- 2. Enter frmgr.
Circuit <NET-1> frmgr
Frame Relay Manager Console
FRMGR <WAN>
Displaying the FRLANE Prompts
To display the FRLANE configuration prompt (FRMGR Config <WAN>),
- 1. At the Config> prompt, enter list interfaces to see a list of interfaces configured on the router.
- 2. If you have not already done so, set the data-link protocol for an interface to Frame Relay.
Config>set data-link frame-relay
Interface Number [0]? 1
- 3. Enable Frame Relay LAN Emulation on the Frame Relay interface.
Config>enable lan-emulation
Interface number [0]? 1
- 4. Enter the network command to display the circuit configuration prompt. The network number is the number of the Frame Relay interface.
Config>network
What is the network number [0]? 1
Circuit Configuration
Circuit Config <NET-1>
- 5. Enter frlane.
Circuit Config <NET-1> frlane
Frame Relay LAN Emulation User Configuration
FRLANE Config <NET-1>
To display the FRLANE monitoring prompt (FLANE <NET-#>),
- 1. At the monitoring prompt (+), enter list interfaces to see a list of interfaces configured on the router. Enter network followed by the number of the Frame Relay interface that you want to monitor.
+network 1
Circuit <NET-1>
- 2. Enter frlane.
Circuit <NET-1> frlane
Frame Relay LAN Emulation Console
FRLANE <NET-1>
Displaying the FRVC Prompt
There is no configuration prompt for FRVC. There is a monitoring prompt that you can use to list and clear statistics for the circuit. To display the FRVC monitoring prompt (FRVC <NET-#>),
- 1. At the monitoring prompt (+), enter list interfaces to see a list of interfaces configured on the router.
- 2. Enter network followed by the number of the Frame Relay interface that you want to monitor.
+network 1
Circuit <NET-1>
- 3. Enter frvc.
Circuit <NET-1> frvc
Frame Relay Virtual Circuit Console
FRVC <NET-1>
Configuring Frame Relay
To configure Frame Relay, you need to do the following:
- 1. Fill out the Frame Relay worksheet
- 2. Configure FRMGR
- 3. Configure FRLANE
And/Or
- 4. Configure FRVC
See Choosing Between FRLANE and FRVC.
The next sections describe each of these tasks. Once you finish configuring Frame Relay, restart the router for your configuration to take effect.
Frame Relay Worksheet
To configure Frame Relay, you need the following information. Your Frame Relay provider or network administrator can give you this information.
Configuring Frame Relay Manager
Follow these steps to configure the Frame Relay Manager (FRMGR).
- 1. Follow the steps in Displaying the FRMGR Prompts to display the FRMGR Config <WAN> prompt.
- 2. Add a PVC. This step is optional except in certain situations, listed under add permanent virtual circuit.
FRMGR Config <WAN> add permanent-virtual-circuit
Circuit number [16]?
Committed Information Rate (CIR) in bps [64000]?
Committed Burst Size (Bc) in bits [64000]?
Excess Burst Size (Be) in bits [0]?
Assign circuit name? rochester
- 3. If your Frame Relay supplier uses an LMI type other than ANSI Annex D, change the LMI type to LMI Revision 1 (Rev1) or CCITT.
FRMGR Config <WAN> set lmi-type rev1
Configuring HDLC Parameters
You can adjust the following HDLC parameters, if necessary.
* Not configurable on all platforms. Some platforms automatically detect the cable type and set clocking to internal or external.
To set these parameters, enter sl at the circuit configuration prompt, and then use the set hdlc commands.
Circuit Config <NET-1> sl
Serial Line Configuration
Serial Config <WAN> set hdlc Space
The choices/prefixes are (a complete list):
CABLE
CLOCKING
ENCODING
FRAME-SIZE
IDLE
SPEED
TRANSMIT-DELAY
Configuring Frame Relay over ISDN
To run Frame Relay over an ISDN interface, set the name of the destination to call to establish a connection with the Frame Relay switch. Add the same address name, along with the dial address (telephone number) of the Frame Relay switch, using the add address ISDN configuration command at the BRI Config <WAN>.
FRMGR Config <WAN2-1> set switch-address-name
Assign switch address name? rochester
You can also use the set idle-timeout and set redial-timer commands to control connections to the Frame Relay switch.
For information on how to set up ISDN, see Using the ISDN Interface.
Configuring Frame Relay LAN Emulation
Follow these steps to configure FRLANE.
- 1. Configure the Frame Relay Manager as described in Configuring Frame Relay Manager.
- 2. If you need multiple FRLANE interfaces running on a Frame Relay device, add Frame Relay interfaces.
Config>add interface frame-relay
Adding interface 2 linked to base device WAN.
- 3. Enable LAN emulation on each interface over which you are running FRLANE.
Config>enable lan-emulation
Interface number [0]? 1
Config>enable lan-emulation
Interface number [0]? 2
- 4. Follow the steps in Displaying the FRLANE Prompts to display the FRLANE Config <NET-#> prompt.
- 5. Add a circuit. This step is optional unless you run bridging or IPX over FRLANE, or you want to set up the circuit as required to trigger WAN Reroute.
To run IPX or bridging over the FRLANE interface, in the FRMGR configuration, add a PVC that has the same number as the circuit you add here and optionally assign a name to the PVC.
FRLANE Config <NET-1> add circuit
Circuit number [16]?
Is circuit required for interface operation? [N]?
- 6. To allow FRLANE to use only circuits that you added, and not circuits that it learns about from FRMGR, enable a LAN emulation group. See LAN Emulation Groups.
FRLANE Config <NET-1> enable lane-group
- 7. Add static destination protocol addresses to connect with devices that do not support Inverse ARP.
FRLANE Config <NET-1> add protocol-address
Protocol name or number [IP]?
IP Address [0.0.0.0]? 10.1.65.3
- 8. Repeat step 4 through step 7 for each FRLANE interface.
Configuring Frame Relay Virtual Circuit (FRVC)
Follow these steps to configure an FRVC interface.
- 1. Configure FRMGR as described in Configuring Frame Relay Manager.
- 2. If you need multiple FRVC interfaces running on the same Frame Relay device, add Frame Relay interfaces.
Config>add interface frame-relay
Adding interface 2 linked to base device WAN.
- 3. FRVC is the default for new Frame Relay interfaces. However, if you previously enabled LAN emulation, disable it on each interface over which you are running FRVC.
Config>disable lan-emulation
Interface number [0]? 2
- 4. Set a destination for this FRVC at the circuit configuration prompt. The address name that you assign is the name or DLCI of a PVC that you added in the FRMGR configuration using the add permanent-virtual-circuit command, or the DLCI of an orphan circuit.
Config>network
What is the network number [0]? 2
Circuit Configuration
Circuit Config <NET-2> set destination
Assign destination address name []? rochester
There is no configuration prompt for FRVC. There is a monitoring prompt that you can use to list and clear statistics. See Displaying the FRVC Prompt. For a description of the FRVC commands, see FRVC Commands.
Running PPP over FRVC
You can optionally set up an FRVC to send PPP data over the FRVC. By also enabling PPP data compression, you can compress the data that the router sends over the FRVC. To use PPP over FRVC, enable it at the configuration prompt and then set up PPP as you normally would.
Config>enable ppp-over-frvcInterface Number [0]? 2 Note:
Make sure you also enable PPP over FRVC on the remote router to which this FRVC connects.
FRMGR Commands
This section describes the Frame Relay Manager (FRMGR) commands. Note:
The FRMGR configuration applies to all interfaces on a physical Frame Relay device. If you have multiple interfaces on one device, it does not matter which Circuit Config <NET-#> prompt for the device you use to get to the FRMGR prompt.
Press Space twice after you type a command to display the available options for each command. Enter help for information about using the command line interface.
[C] means the command is available at the FRMGR Config <WAN> prompt.
[M] means the command is available at the FRMGR <WAN> prompt.
Add [C]
Adds a PVC to the FRMGR configuration. Add a PVC if you
Syntax: add
- permanent-virtual-circuit
permanent-virtual-circuit
Adds a PVC to the FRMGR configuration beyond the reserved range of 0 through 15. The maximum number of PVCs that you can add is 992, but the actual number of PVCs that the device can support is affected by the configured size of the receive buffers on the device. (You can add a circuit that has the same number as a circuit configured in the FRLANE configuration.)
Example: add permanent-virtual-circuit
Circuit Number [16]?
Committed Information Rate (CIR) in bps [64000]?
Committed Burst Size (Bc) in bits [64000]?
Excess Burst Size (Be) in bits [0]?
Assign Circuit name []?
Change [C]
Changes the configuration of PVCs.
Syntax: change
- permanent-virtual-circuit
permanent-virtual-circuit
Changes the configuration of a PVC that you added with the add permanent-virtual-circuit command.
Example: change permanent-virtual-circuit
Circuit Number [16]?
Committed Information Rate in bps [64000]?
Committed Burst Size (Bc) in bits [64000]?
Excess Burst Size (Be) in bits [0]?
Assign Circuit Name: []?
Clear [M]
Resets all FRMGR statistics on the Frame Relay device.Note:
You can also clear statistics using the clear command at the + prompt.
Syntax: clear
Example: clear
Delete [C]
Deletes PVCs from the FRMGR configuration.
Syntax: delete
- permanent-virtual-circuit
permanent-virtual-circuit
Deletes a PVC that you added using the add permanent-virtual-circuit command.
Example: delete permanent-virtual-circuit
Circuit number [16]? 20
Disable [C] [M]
Disables FRMGR features that are enabled.
Syntax: disable
- cir-monitor
- congestion-monitor
- lmi
- orphan-circuits
cir-monitor
Disables the circuit monitoring feature that enforces the committed information rate. The default is disabled.
Example: disable cir-monitor
congestion-monitor
Disables congestion monitoring, which prevents FRMGR from varying the circuit's information rate in response to network congestion. The default is enabled.
Example: disable congestion-monitor
lmi
Disables all management activity. The default is LMI ANSI enabled. Disabling LMI causes the software to mark all PVCs that you added as present and active. If the status of a PVC changes, FRMGR has no way to learn of the change. FRMGR also has no way to learn about orphan circuits. This command is available only at the FRMGR Config <WAN> prompt.Note:
Disabling LMI allows for normal operation or end-to-end Frame Relay testing in the absence of a real network or management interface. For end-to-end Frame Relay testing, add PVCs on both ends of the link and assign the same circuit number to them.
Example: disable lmi
orphan-circuits
Prohibits the use of orphan circuits on the device. The default is orphan circuits enabled. Disabling orphan circuits adds a measure of security to your network by preventing unauthorized entry into your network from a nonconfigured circuit.
This command is available only at the FRMGR Config <WAN> prompt.
Example: disable orphan-circuits
Enable [C] [M]
Enables circuit and congestion monitoring, LMI, and the use of orphan circuits.
Syntax: enable
- cir-monitor
- congestion-monitor
- lmi
- orphan-circuits
cir-monitor
Enables the circuit monitoring feature that enforces the committed information rate. The default is disabled.
See CIR Monitoring.
Example: enable cir-monitor
congestion-monitor
Enables congestion monitoring, which allows a circuit's information rate to vary in response to network congestion. The default is enabled.
See Congestion Monitoring.
Example: enable congestion-monitor
lmi
Enables management activity. The default is LMI ANSI enabled. Use enable lmi to resume LMI management if you previously disabled LMI.
Use the set lmi-type command to change the management type.
This command is available only at the FRMGR Config <WAN> prompt.
Example: enable lmi
orphan-circuits
Allows FRMGR to use orphan circuits, which is the default. The CIR of orphan circuits is 64000 bps, the committed burst (Bc) size is 64000 bps, and the excess burst (Be) size is 0.
This command is available only at the FRMGR Config <WAN> prompt.
Example: enable orphan-circuits
Exit [C] [M]
Returns to the previous prompt.
Syntax: exit
Example: exit
Circuit Config <NET-1>
List [C] [M]
This section explains list commands available at the FRMGR configuration and monitoring prompts.
List [C]
Displays currently configured management and PVC information.
Syntax: list
- all
- lmi
- permanent-virtual-circuits
all
Comprehensively displays the output of the other list command options.
lmi
Displays logical management and related configuration information.
Example: list lmi
Frame Relay LMI Configuration
LMI enabled = Yes LMI DLCI = 0
LMI type = ANSI LMI Orphans OK = Yes
Congestion monitoring = Yes CIR monitoring = No
PVCs P1 allowed = 64 CIR monitor adjustment = 1
Timer T1 seconds = 10 Counter N1 increments = 6
LMI N2 error threshold = 3 LMI N3 error threshold window = 4
MIR % of CIR = 25 IR % increment = 12
IR % decrement = 25 Redial timer = 0
Idle timeout = 0
Switch address name = seattle
permanent-virtual-circuits
Displays all PVCs configured on the FRMGR.
Example: list permanent-virtual-circuit
Maximum PVCs allowable = 64
Total PVCs configured = 2
Circuit Circuit Circuit CIR Burst Excess
Name Number Type in bps Size Burst
-------------------- ------- ------- ------ ----- -----
houston 16 Permanent 64000 64000 0
portland 32 Permanent 64000 64000 0
List [M]
Displays statistics and configuration information.
Syntax: list
- all
- circuit
- lmi
- permanent-virtual-circuits
all
Comprehensively displays the output of the other list command options.
circuit
Displays statistics and configuration information for the circuit that you specify.
Example: list circuit
Circuit number [16]?
Circuit name = houston
Circuit state = Idle Circuit is orphan = No
Frames transmitted = 0 Bytes transmitted = 0
Frames received = 0 Bytes received = 0
Total FECNs = 0 Total BECNs = 0
Times congested = 0 Times Inactive = 0
CIR in bits/second = 9600 Current Info Rate = 9600
Committed Burst (Bc) = 64000 Excess Burst (Be) = 0
Xmit frames dropped due to queue overflow = 0
lmi
Displays statistics and configuration information related to the logical management of the Frame Relay device.
Example: list lmi
Management Status:
------------------
LMI state = Initial
LMI enabled = Yes LMI DLCI = 0
LMI type = ANSI LMI orphans OK = Yes
LMI sequence interval seconds = 10
Congestion monitoring = Yes CIR monitoring = No
PVCs P1 allowed = 64 Interface MTU in bytes = 2048
Line access rate bps = 9600 CIR monitor adjustment = 1
Timer T1 seconds = 10 Counter N1 increments = 6
LMI N2 threshold = 3 LMI N3 threshold window = 4
MIR % of CIR = 25 IR % increment = 12
IR % decrement = 25 Redial timer = 0
Idle timeout = 0
Switch address name =
Current receive sequence = 0
Current transmit sequence = 0
Total status enquiries = 0 Total status responses = 0
Total sequence requests = 0 Total responses =
PVC Status:
-----------
Total allowed = 64 Total configured = 1
Total active = 0 Total congested = 0
Total left net = 0 Total join net = 0
permanent-virtual-circuits
Shows the circuits that FRMGR knows about, either PVCs or orphan circuits.
Example: list permanent-virtual-circuits
Orphan Type/ Frames Frames
Circuit# Circuit Name Circuit State Transmitted Received
-------- ------------------------ ------- ----- ----------- ----------
16 houston No P/I 0 0
A - Active I - Inactive R - Removed
P - Permanent M - Multicast C - Congested
Remove [C]
Deletes PVCs from the FRMGR configuration.
Syntax: remove
- permanent-virtual-circuit
permanent-virtual-circuit
Deletes a PVC that you added using the add permanent-virtual-circuit command.
Example: remove permanent-virtual-circuit
Circuit number [16]? 20
Set [C] [M]
This section explains set commands available at the FRMGR configuration and monitoring prompts.
Set [C]
Sets the Frame Relay management options, idle timeout, redial timer, and a switch address name.
Syntax: set
- idle-timeout
- ir-adjustment
- lmi-type
- n1-parameter
- n2-parameter
- n3-parameter
- p1-parameter
- redial-timer
- switch-address-name
- t1-parameter
idle-timeout
For Frame Relay over ISDN connections, sets the number of seconds FR waits after connecting to the FR switch before it disconnects if no upper-layer protocol requests to use the connection to the switch.
The default is 60. The range is 1 to 65535 seconds.
Example: set idle-timeout
Idle timeout in seconds (1-65535) [60]?
ir-adjustment
Sets the minimum Information Rate (IR) and the percentages for increasing and decreasing the IR in response to network congestion.
When network congestion clears, each time the router receives a frame without BECN, it increases the IR by this percentage until it reaches the maximum IR. The minimum percentage is 1, and the maximum percentage is 100. The default is 12.
When network congestion occurs, each time the router receives a frame containing BECN, it decreases the IR by this percentage until it reaches the minimum IR. The minimum percentage is 1, and the maximum percentage is 100. The default is 25.
The minimum IR is a percentage of CIR, and is the lower limit of the information rate. The minimum percentage is 1, and the maximum percentage is 100. The default is 100.
See Congestion Notification and Avoidance.
Example: set ir-adjustment
IR adjustment % increment [12]?
IR adjustment % decrement [25]?
Minimum IR as % of CIR [100]?
lmi-type
Sets the management type that is in use on the Frame Relay network. The default is ANSI. Check with your Frame Relay service provider to find out which management type to use.
Example: set lmi-type ansi
n1-parameter
Sets the number of T1 timer intervals that must expire before Frame Relay makes a complete PVC status enquiry. The range is 5 to 30. The default is 2.
Example: set n1-parameter
Parameter N1 [2]?
n2-parameter
Sets the number of errors that can occur in the management event window that the n3-parameter monitors before the Frame Relay connection resets. See Managing Errors.
The range is 1 to 10. The default is 3. Set this parameter less than or equal to the n3-parameter.
Example: set n2-parameter
Parameter N2 [3]?
n3-parameter
Sets the number of monitored management events for measuring the n2-parameter. See Managing Errors. The range is 1 to 10. The default is 4.
Example: set n3-parameter
Parameter N3 [4]?
p1-parameter
Sets the maximum number of PVCs that FRMGR supports. The range is 0 to 992. The default is 64. A 0 (zero) implies that the device supports no PVCs.
Example: set p1-parameter
Parameter P1 [64]?
redial-timer
Use this parameter in Frame Relay over ISDN configurations. It causes FRMGR to reconnect to the Frame Relay switch automatically after being disconnected. Doing so allows FRMGR to periodically check the status of virtual circuits.
The default of 0 (zero) means FRMGR does not redial automatically. To set up FRMGR to redial automatically, enter the number of seconds FRMGR waits after it disconnects before attempting another connection. The range is 0 to 65535 seconds.
Example: set redial-timer
Redial timer in seconds (0-65535, 0 means no redial) [0]?
switch-address-name
To run Frame Relay over ISDN, add a switch address name. This is the address name of the Frame Relay switch to which you are connecting. You must add the same address name along with the dial address (telephone number) of the Frame Relay switch using the add address ISDN configuration command at the BRI Config <WAN>.
Example: set switch-address-name
Assign switch address name? seattle
t1-parameter
Sets the interval in seconds that FRMGR takes to perform a sequence number exchange with Frame Relay management. The management's T2 timer is the allowable interval for an end station to request a sequence number exchange with the manager. Set the T1 interval less than the T2 interval of the network. The range is 5 to 30. The default is 10.
Example: set t1-parameter
Parameter T1 [10]?
Set [M]
This section explains set commands available at the FRMGR monitoring prompt. These commands take affect immediately, and the software does not save any changes you make with these commands when you restart the router.
Syntax: set
- circuit
- ir-adjustment
circuit
Dynamically changes the configuration of a PVC that you added with the add permanent-virtual-circuit command.
Example: set circuit
Circuit Number [16]?
Committed Information Rate in bps [64000]?
Committed Burst Size (Bc) in bits [64000]?
Excess Burst Size (Be) in bits [0]?
ir-adjustment
Dynamically sets the minimum Information Rate (IR) and the percentages for increasing and decreasing the IR in response to network congestion.
When network congestion clears, each time the router receives a frame without BECN, it increases the IR by this percentage until it reaches the maximum IR. The minimum percentage is 1, and the maximum percentage is 100. The default is 12.
When network congestion occurs, each time the router receives a frame containing BECN, it decreases the IR by this percentage until it reaches the minimum IR. The minimum percentage is 1, and the maximum percentage is 100. The default is 25.
The minimum IR is a percentage of CIR, and is the lower limit of the information rate. The minimum percentage is 1, and the maximum percentage is 100. The default is 100.
Example: set ir-adjustment
IR adjustment % increment [12]?
IR adjustment % decrement [25]?
Minimum IR as % of CIR [100]?
FRLANE Commands
This section describes the FRLANE commands.
Press Space twice after you type a command to display the available options for each command. Enter help for information about using the command line interface.
[C] means the command is available at the FRLANE Config <NET-#> prompt.
[M] means the command is available at the FRLANE <NET-#> prompt.Note:
To display these prompts, you must first enter enable lan-emulation at the Config> prompt.
Add [C]
Adds a circuit or destination protocol address.
Syntax: add
- circuit
- protocol-address
circuit
Adds a circuit to the FRLANE interface beyond the reserved range of 0 through 15. The maximum number of circuits that you can add is 992, but the actual number of circuits that the interface can support is affected by the configured size of the receive buffers on the device. Assign a circuit number that is the same as the DLCI of a circuit configured in the FRMGR configuration or an orphan circuit.
To run IPX or bridging over FRLANE,
- 1. Add a circuit here.
- 2. In the FRMGR configuration, add a PVC that has the same number as the circuit you add here and assign a name to the PVC. See add permanent virtual circuit.
For WAN Reroute operation, you can configure a circuit as required, which causes the FRLANE interface to declare itself down if the circuit becomes unavailable. WAN Reroute uses this as a trigger to bring up the alternate link.
Configuring a circuit as required causes all circuits on the FRLANE interface to go down when a required circuit becomes unavailable. Instead of configuring a circuit as required to trigger WAN Reroute, you can enter enable no-pvc, which causes the interface to declare itself down if there are no active circuits.
Example: add circuit
Circuit Number [16]?
Is circuit required for interface operation? [N]?
protocol-address
Adds static destination protocol addresses to the FRLANE interface. You may need to add an address if a remote Frame Relay device does not support Inverse ARP. You can also add static address mappings to reduce broadcast traffic. See Address Mapping.
This parameter prompts you for different information depending on the type of protocol address you are adding.
Example: add protocol-address
Protocol name or number [IP]?
IP protocol:
IP Address [0.0.0.0]?
Circuit number [16]?
IPX protocol:
Host Number (in hex)[]?
Circuit number [16]?
AppleTalk:
Network number (1-65279) []?
Node number (1-253) []?
Circuit number [16]?
Change [C]
Changes circuits or protocol addresses that were added with the add command.
Syntax: change
- circuit
- protocol-address
circuit
Sets whether or not a circuit that you added is required. Configure a circuit as required to cause the FRLANE interface to declare itself down if the circuit becomes unavailable. WAN Reroute uses this as a trigger to bring up the alternate link.
Configuring a circuit as required causes all circuits on the interface to go down when a required circuit becomes unavailable. Instead of configuring a circuit as required to trigger WAN Reroute, you can enter enable no-pvc, which causes the interface to declare itself down if there are no active circuits.
Example: change circuit
Circuit number [16]?
Is circuit required for interface operation? [N]? y
protocol-address
Changes a destination protocol address that you added to a circuit.
Example: change protocol-address
Protocol name or number [IP]?
IP Address [0.0.0.0]? 128.185.10.2
Circuit number [16]?
Clear [M]
Resets FRLANE statistics on this FRLANE interface.
Syntax: clear
Example: clear
Delete [C]
Deletes circuits or protocol addresses that you added with the add command.
Syntax: delete
- circuit
- protocol-address
circuit
Deletes circuits that you added with the add circuit command.
Example: delete circuit
Circuit number [16]?
protocol-address
Deletes destination protocol addresses that you added with the add protocol-address command.
Example: delete protocol-address
Protocol name or number [IP]?
IP Address [0.0.0.0]? 128.185.10.2
Circuit number [16]?
Disable [C] [M]
Disables LAN emulation groups, multicast-emulation, protocol-broadcast, and the no-PVC flag.
Syntax: disable
- lane-group
- multicast-emulation
- protocol-broadcast
- no-pvc
lane-group
Lets FRLANE use available circuits that it learns about dynamically from FRMGR in addition to circuits that you added manually.
Example: disable lane-group
multicast-emulation
Disables multicast emulation on all active VCs on this interface. Multicast emulation allows protocols requiring multicast to work properly over the FRLANE interface. Protocols that use multicast are IP, IPX, and ARP. The default setting for this feature is enabled. If you disable this feature, you must add static destination protocol addresses.
Example: disable multicast-emulation
protocol-broadcast
Prevents routing protocols that use broadcasts, such RIP, from running over the FRLANE interface. The default setting for this feature is enabled.
Example: disable protocol-broadcast
no-pvc
Disables the no-PVC flag on the FRLANE interface. The WAN Reroute feature uses the no-PVC flag. When enabled, this flag triggers WAN Reroute to bring up the alternate circuit by causing the interface to declare itself down if there are no active circuits.
Example: disable no-pvc
Enable [C] [M]
Enables LAN emulation groups, multicast-emulation, protocol-broadcast, and the no-PVC flag.
Syntax: enable
- lane-group
- multicast-emulation
- protocol-broadcast
- no-pvc
lane-group
Allows FRLANE to use only circuits that you added manually. FRLANE cannot use circuits that it learns about dynamically from FRMGR.
Example: enable lane-group
multicast-emulation
Enables multicast emulation on all active VCs on this interface. Multicast emulation allows protocols requiring multicast to work properly over the FRLANE interface. Protocols that use multicast are IP, IPX, and ARP. The default is enabled.
Example: enable multicast-emulation
protocol-broadcast
Allows routing protocols that use broadcasts, such as RIP, to run over the FRLANE interface. Multicast emulation must be enabled for protocol broadcast to work properly. The default setting for this feature is enabled.
Example: enable protocol-broadcast
no-pvc
Enables the no-PVC flag on the FRLANE interface. The WAN Reroute feature uses the no-PVC flag. When enabled, this flag triggers WAN Reroute to bring up the alternate circuit by causing the interface to declare itself down if there are no active circuits available.
Example: enable no-pvc
Exit [C] [M]
Returns to the previous prompt.
Syntax: exit
Circuit Config <NET-1>
List [C] [M]
This section explains list commands available at the FRLANE configuration and monitoring prompts.
List [C]
Displays FRLANE VCs, LAN emulation configuration, and any protocol address mappings.
Syntax: list
- all
- circuits
- lane
- protocol-addresses
all
Comprehensively displays the output of the other list command options.
circuits
Displays circuits that you manually added for FRLANE and whether or not the circuits are required.
Example: list circuits
Frame Relay LAN Emulation Configured Circuits
Circuit# Required
-------- --------
16 No
lane
Displays the LAN emulation configuration.
Example: list lane
Frame Relay LAN Emulation Configuration
LANE emulation group = Disabled
Protocol broadcast = Yes Multicast emulation = No
Down if no circuits = No
protocol-addresses
Displays protocol addresses that you statically configured using the add protocol-address command.
Example: list protocol-addresses
Frame Relay Protocol Address Translations
Protocol Type Protocol Address Circuit Number
------------- ---------------- --------------
IP 128.185.10.2 16
List [M]
Displays statistics and configuration information for FRLANE circuits.
Syntax: list
- all
- circuit
all
Displays LAN emulation configuration, state information, and circuit statistics.
Example: list all
Frame Relay LAN Emulation
State = Up
LAN emulation group = Disabled
Protocol broadcast = No Emulate multicast = Yes
Down if no circuits = No
Active circuits = 0 Total circuits = 1
Type/ Frames Frames
Circuit# Circuit Name State Transmitted Received
-------- ------------------------ ------ ----------- ----------
16 houston S/I 0 0
D - Dynamic S - Static * - Required
A - Active I - Inactive
circuits
Displays statistics for the circuit that you specify.
Example: list circuit
Circuit number [16]?
Circuit name = houston
Circuit state = Inactive
Frames transmitted = 0 Bytes transmitted = 0
Frames received = 0 Bytes received = 0
Remove [C]
Deletes circuits or protocol addresses that you added with the add command.
Syntax: remove
- circuit
- protocol-address
circuit
Deletes circuits that you added with the add circuit command.
Example: remove circuit
Circuit number [16]?
protocol-address
Deletes destination protocol addresses that you added with the add protocol-address command.
Example: remove protocol-address
Protocol name or number [IP]?
IP Address [0.0.0.0]? 128.185.10.2
Circuit number [16]?
FRVC Commands
This section describes the Frame Relay Virtual Circuit (FRVC) commands.
Press Space twice after you type a command to display the available options for each command. Enter help for information about using the command line interface.
There is no configuration prompt for FRVC.
[M] means the command is available at the FRVC <NET-#> prompt.
Clear [M]
Clears all statistics for Frame Relay Virtual Circuits.
Syntax: clear
Example: clear
Exit [M]
Returns to the previous prompt.
Syntax: exit
Example: exit
Circuit <NET-1>
List [M]
Displays statistics for the virtual circuit.
Syntax: list
Example: list
Frame Relay Virtual Circuit
Circuit name =
State = Down
Frames transmitted = 0 Bytes transmitted = 0
Frames received = 0 Bytes received = 0
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