Difference between revisions of "VPP/MFIB"
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| − | === | + | = MFIB = |
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| + | == 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. | 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. | ||
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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: | ||
| − | ip mroute add 1.1.1.1 239.1.1.1 via Eth0/0 | + | ip mroute add 1.1.1.1 239.1.1.1 via Eth0/0 Forward |
| − | ip mroute add 1.1.1.1 239.1.1.1 via Eth0/1 | + | ip mroute add 1.1.1.1 239.1.1.1 via Eth0/1 Forward |
the flag 'Forwarding' passed with the path specifies this path to be part of the replication set. | 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: | 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 | |
| + | |||
| + | A (*,G) entry is added by not specifying a source address: | ||
| + | ip mroute add 232.2.2.2 via Eth0/2 Forward | ||
| + | |||
| + | A (*,G/m) entry is added by not specifying a source address and giving the group address a mask: | ||
| + | ip mroute add 232.2.2.0/24 via Eth0/2 Forward | ||
Revision as of 16:07, 5 December 2018
MFIB
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 Forward ip mroute add 1.1.1.1 239.1.1.1 via Eth0/1 Forward
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
A (*,G) entry is added by not specifying a source address:
ip mroute add 232.2.2.2 via Eth0/2 Forward
A (*,G/m) entry is added by not specifying a source address and giving the group address a mask:
ip mroute add 232.2.2.0/24 via Eth0/2 Forward
