Difference between revisions of "VPP/MFIB"
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=== Basics === | === Basics === | ||
| − | An IP multicast FIB (mFIB) is a data-structure that holds entries that represent a (S,G) or a (*,G) multicast group. There is one IPv4 and one IPv6 mFIB per IP table, i.e. each time | + | An IP multicast FIB (mFIB) is a data-structure that holds entries that represent a (S,G) or a (*,G) multicast group. There is one IPv4 and one IPv6 mFIB per IP table, i.e. each time the user calls 'ip[6] table add X' an mFIB is created. |
| − | A path describes either where a | + | |
| + | A path describes either where a packet is sent to or where a packet is received from. mFIB entries maintain two sets of 'paths'; the forwarding set and the accepting set. Each path in the forwarding set will output a replica of a received packet. A received packet is only accepted for forwarding if it ingresses on a path that matches in the accepting set - this is the RPF check. | ||
To add an entry to the default mFIB for the group (1.1.1.1, 239.1.1.1) that will replicate packets to Eth0/0 and Eth0/1, do: | To add an entry to the default mFIB for the group (1.1.1.1, 239.1.1.1) that will replicate packets to Eth0/0 and Eth0/1, do: | ||
Revision as of 15:57, 5 December 2018
Basics
An IP multicast FIB (mFIB) is a data-structure that holds entries that represent a (S,G) or a (*,G) multicast group. There is one IPv4 and one IPv6 mFIB per IP table, i.e. each time the user calls 'ip[6] table add X' an mFIB is created.
A path describes either where a packet is sent to or where a packet is received from. mFIB entries maintain two sets of 'paths'; the forwarding set and the accepting set. Each path in the forwarding set will output a replica of a received packet. A received packet is only accepted for forwarding if it ingresses on a path that matches in the accepting set - this is the RPF check.
To add an entry to the default mFIB for the group (1.1.1.1, 239.1.1.1) that will replicate packets to Eth0/0 and Eth0/1, do:
ip mroute add 1.1.1.1 239.1.1.1 via Eth0/0 Forwarding ip mroute add 1.1.1.1 239.1.1.1 via Eth0/1 Forwarding
the flag 'Forwarding' passed with the path specifies this path to be part of the replication set. To add a path from Eth0/2 to the accepting (RPF) set do:
ip mroute add 1.1.1.1 239.1.1.1 via Eth0/2 Accept
