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Diffstat (limited to 'docs/gettingstarted')
| -rw-r--r-- | docs/gettingstarted/developers/fib20/index.rst | 1 | ||||
| -rw-r--r-- | docs/gettingstarted/developers/fib20/mplsfib.rst | 8 | ||||
| -rw-r--r-- | docs/gettingstarted/developers/fib20/multicast.rst | 88 |
3 files changed, 94 insertions, 3 deletions
diff --git a/docs/gettingstarted/developers/fib20/index.rst b/docs/gettingstarted/developers/fib20/index.rst index acd290089ca..535e15662d6 100644 --- a/docs/gettingstarted/developers/fib20/index.rst +++ b/docs/gettingstarted/developers/fib20/index.rst @@ -9,4 +9,5 @@ FIB 2.0 Hierarchical, Protocol, Independent thedatamodel tunnels mplsfib + multicast fastconvergence diff --git a/docs/gettingstarted/developers/fib20/mplsfib.rst b/docs/gettingstarted/developers/fib20/mplsfib.rst index c9f3d5d9ad1..6b14732214b 100644 --- a/docs/gettingstarted/developers/fib20/mplsfib.rst +++ b/docs/gettingstarted/developers/fib20/mplsfib.rst @@ -89,9 +89,11 @@ actions are: These can be programmed respectively by: -#. mpls local-label 33 eos ip4-lookup-in-table X -#. mpls local-label 33 [eos] via 10.10.10.10 GigEthernet0/0/0 -#. mpls local-label 33 [eos] via 10.10.10.10 GigEthernet0/0/0 out-labels 66 +.. code-block:: console + + $ mpls local-label 33 eos ip4-lookup-in-table X + $ mpls local-label 33 [eos] via 10.10.10.10 GigEthernet0/0/0 + $ mpls local-label 33 [eos] via 10.10.10.10 GigEthernet0/0/0 out-labels 66 the latter is an example of an MPLS cross connect. Any description of a next-hop, recursive, non-recursive, labelled, non-labelled, etc, diff --git a/docs/gettingstarted/developers/fib20/multicast.rst b/docs/gettingstarted/developers/fib20/multicast.rst new file mode 100644 index 00000000000..15bcddfec46 --- /dev/null +++ b/docs/gettingstarted/developers/fib20/multicast.rst @@ -0,0 +1,88 @@ +.. _mfib: + +IP Multicast FIB +---------------- + +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 GigEthernet0/0/0 and GigEthernet0/0/1, do: + +.. code-block:: console + + $ ip mroute add 1.1.1.1 239.1.1.1 via GigEthernet0/0/0 Forward + $ ip mroute add 1.1.1.1 239.1.1.1 via GigEthernet0/0/1 Forward + +the flag 'Forward' passed with the path specifies this path to be part of the replication set. +To add a path from GigEthernet0/0/2 to the accepting (RPF) set do: + +.. code-block:: console + + $ ip mroute add 1.1.1.1 239.1.1.1 via GigEthernet0/0/2 Accept + +A (\*,G) entry is added by not specifying a source address: + +.. code-block:: console + + $ ip mroute add 232.2.2.2 via GigEthernet0/0/2 Forward + +A (\*,G/m) entry is added by not specifying a source address and giving +the group address a mask: + +.. code-block:: console + + $ ip mroute add 232.2.2.0/24 via GigEthernet0/0/2 Forward + +Entries are deleted when all paths have been removed and all entry flags (see below) are also removed. + +Advanced +^^^^^^^^ + +There are a set of flags associated only with an entry, see: + +.. code-block:: console + + $ show mfib route flags + +only some of these are relevant over the API/CLI: + +#. Signal - packets that match this entry will generate an event that + is sent to the control plane (which can be retrieved via the signal + dump API) +#. Connected - indicates that the control plane should be informed of + connected sources (also retrieved via the signal dump API) +#. Accept-all-itf - the entry shall accept packets from all + interfaces, thus eliminating the RPF check +#. Drop - Drop all packet matching this entry. + +flags on an entry can be changed with: + +.. code-block:: console + + $ ip mroute <PREFIX> <FLAG> + +An alternative approach to the RPF check, that does check the +accepting path set, is to give the entry and RPF-ID: + +.. code-block:: console + + $ ip mroute <PREFIX> rpf-id X + +the RPF-ID is an attribute of a received packet's meta-data and is +added to the packet when it ingresses on a given entity such as an +MPLS-tunnel or a BIER table disposition entry. |