TLVs

This information is propagated through the SPBM cloud using IS-IS Link State Packets (LSPs), which carry TLV updates, that result in the multicast tree creation for that stream. The LSPs carry I-SID information and information about where IP multicast stream senders and receivers exist using the following TLVs :

• For Layer 2 VSNs and Layer 3 VSNs, using TLV 144 and TLV 185.
• For IP Multicast over Fabric Connect within the GRT, using TLV 144 and TLV 186.

TLV 144 on the BEB bridge, where the sender is located, has the Tx bit set. All BEB bridges, where a receiver exists, have the Rx bit set.

TLV 185 on the BEB where the source is located, displays the multicast source and group addresses and has the Tx bit set.

TLV 186 on the BEB where the source is located displays the multicast source and group addresses and have the Tx bit set.

Each multicast group has its own unique data I-SID with a value between 16,000,000 to 16,512,000.

IS-IS acts dynamically using the TLV information received from BEBs that connect to the sender and the receivers to create a multicast tree between them.