15-2 Frame Relay Module 4.0 User Guide, Rev 01Incoming LLC2 traffic that is destined for a terminated MAC address will be for-warded to the node's internal LLC2 processes. Non-terminated LLC2 frames and allother frames will be forwarded to the bridge.Under the spanning tree concept, bridges automatically maintain forwarding tables viaexchange of messages with other bridges on the network, and determination of singlepaths for traffic between endpoints (assuming there are multiple possible paths).Each Bridge is identified by a Bridge ID, which is made up of a two-octet Bridge Pri-ority—configured in Bridge Node Defaults—followed by a unique 48-bit ID. If thenode contains a LAN card, the 48-bit ID will be the MAC address of the first LANcard to send its status (active/inactive). If there is no LAN card, an address will becreated automatically by the software.Bridging is supported on Ethernet, Token Ring, and frame relay interfaces.The interfaces used for Bridging in the FRM are the same as those used forLLC2. When referring to Bridging, however, these interfaces will be called"Bridge ports," since the IEEE 802.1d standard uses the term "port" toidentify a connection to a bridge.Avoid configuring parallel Bridge/LLC2 frame relay linksbetween two FRM if one path is in native LLC2 format and theother in some other format. Since native LLC2 interfaces do notsupport the spanning tree protocol, a loop can be created,causing a node failure.Required ConfigurationTo configure a Bridge in an FRM, make sure the following are properly configured inthe database:l Node parameters, which is general configuration that must be done no matterwhich protocols will be run in the node. See Chapter 4.l RLPs that will contain the interface(s) to the user device(s), plus Line InterfaceCard(s) supporting the ports that will be the interfaces. See Chapter 5.l Loaded Protocol(s): Bridging, and the transport protocol: frame relay or X.25.See Chapter 5.l LAN interface(s) that will connect to any attached LAN(s). See Chapter 5.l Frame relay port(s) and/or X.25 port(s) that will connect to a network or framerelay PVC. See Chapter 7 (frame relay) or Chapter 8 (X.25).l Bridge parameters, described later in this chapter.
