A number of configuration issues must be addressed before implementing OpenROUTE Networks bridge products to interoperate with the IBM 6611 bridge.
This section provides an overview of these issues, and indicates which features of OpenROUTE Networks bridge implementation are not interoperable with that of the IBM 6611 bridge.
Bridging Configuration Issues
Use this section as a guideline to avoid building an incompatible network topology when using mixed vendor equipment.
The following are bridge configuration issues that you must be aware of when using IBM 6611 bridge and the OpenROUTE Networks bridge products as the two end bridges over serial point-to-point (PPP) links.
All OpenROUTE Networks bridge products support different MAC types (Ethernet, Token Ring and FDDI) over PPP as described in RFC 1638 PPP Bridging Control Protocol.
Currently IBM 6611 bridge supports Ethernet MAC type only over PPP. The RFC 1638 PPP Bridging Control Protocol, (chapter 5.3 MAC-support, page 20), describes how a vendor can announce to the peer bridge what MAC type is supported over PPP so that the peer does not send the unsupported MAC type traffic over PPP.
The OpenROUTE Networks bridge does not drop non-Ethernet frames destined for the PPP network. Neither does it convert all the frames to Ethernet frames before sending them over to PPP. This results in the IBM bridge receiving non-Ethernet frames over PPP and discarding them.
The IBM 6611 bridge supports Token Ring MAC frames, however, when the bridge port associated with PPP is configured as a Source Routing port. This leads to certain restrictions in network topologies when IBM 6611 and OpenROUTE Networks are the two end bridges over the PPP.
Following are examples of network topologies that do not work. Possible alternate configurations (marked Alt) to overcome these problems are suggested below. When considering WAN, LAN types can be extended to MAC types. For example, FDDI can be extended to FDDI MAC type frames from Tunnel/Proteon SL/ other PPP/Frame Relay, and so forth.
Alt: FDDI- Proteon (SR-TB) - PPP (SR) - 6611 (SR-TB)
- Ethernet
Alt: Token Ring (SR) - Proteon (SRB) - PPP (SR) - 6611 (SR-TB) - Ethernet
Alt: Token Ring (SR) - Proteon (SRB) - PPP (SR) - 6611 (SR-TB) - ETH
Alt: Token Ring (SR) - Proteon (SRB) - PPP (SR) - 6611 (SRB) - TKR
Alt: Token Ring (STB) - Proteon (SR-TB) - PPP (SR) - 6611 (SRB) - TKR
Alt: Token Ring (STB) - Proteon (SR-TB) - PPP (SR) - 6611 (SR-TB) - ETH