From: Jongsoo (bstrt2004@gmail.com)
Date: Sat Nov 05 2005 - 21:26:56 GMT-3
Let's say something like
CE1 10.1.1.1---------fe1- PE1- fe0-------CE2 10.1.1.1
In PE1,
ip vrf up
....
ip vrf down
....
Int fe1
ip vrf forwarding down
ip address 10.1.1.2 255.0.0.0
Int fe0
ip vrf forwarding up
ip address 10.1.1.2 255.0.0.0
"ip route vrf up 20.0.0.0 255.255.255.0 fe1"
I understand this static command installs a static route in the VRF
"up" routing table to forward destination address of ip packet
matching 20.0.0.0/24 to fe1, which belongs to VRF down. It will
generate ARP for every different destination address, which consume
memory.
"ip route vrf up 20.0.0.0 255.255.255.0 fe1 10.1.1.1"
a static route in the VRF "up" routing table to forward destination
address of ip packet matching 20.0.0.0/24 to 10.1.1.1 via fe1, which
belongs to VRF down. This won't require a recursive looking in VRF
down routing table because it knows outgoing interface ( of course
except for one time ARP only for 10.1.1.1)
ip route vrf up 30.0.0.0 255.255.255.0 10.1.1.1
installs a static route in the VRF "up" routing table to forward
destination address of ip packet matching 30.0.0.0/24 to 10.1.1.1.
This will require a recursive looking within VRF up routing table in
order to resolve the outgoing interface ( and one time ARPentry only
for 10.1.1.1)
I can also think of
ip route vrf up 30.0.0.0 255.255.255.0 10.1.1.1 global
In this case, outgoing interface resolution occurs in global routing table.
Seems straight forward but multiple static command get very complicated.
I guess "keep it simple" may be the rule of thumb when it comes to
multiple VRF...
Any comment welcome
Jongsoo
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