ANYCAST RP on Nexus 7k
Missing checking possibility
on NX-OS when implementing ANYCAST RP you have to enter all information
regarding RP-address and local and remote Unique loopback-address.
we did our setup according to the TAC document
Anycast RP using PIM (Nexus)
Document ID: 115011
Router RP1:
ip pim rp-address 10.1.1.1 group-list 224.0.0.0/4
ip pim anycast-rp 10.1.1.1 192.168.1.1
ip pim anycast-rp 10.1.1.1 192.168.2.2
interface loopback1
ip address 192.168.1.1/32
ip router ospf 1 area 0.0.0.0
ip pim sparse-mode
interface loopback7
ip address 10.1.1.1/32
ip router ospf 1 area 0.0.0.0
ip pim sparse-mode
Router RP2:
ip pim rp-address 10.1.1.1 group-list 224.0.0.0/4
ip pim ssm range 232.0.0.0/8
ip pim anycast-rp 10.1.1.1 192.168.1.1
ip pim anycast-rp 10.1.1.1 192.168.2.2
ip router ospf 1 area 0.0.0.0
interface loopback1
ip address 192.168.2.2/32
ip pim sparse-mode
interface loopback7
ip address 11.1.1.1/32
ip router ospf 1 area 0.0.0.0
ip pim sparse-mode
so we did (without knowing) 2 errors:
1. the RP address on RP2 has no matching interface (typo on loop 7)
2. we forgot an ospf statement onm a router between both routers
so we had no ip-connectivity between RP1 and RP2
We checked according to the TAC document:
Nexus-1# show ip pim rp
PIM RP Status Information for VRF "default"
BSR disabled
Auto-RP disabled
BSR RP Candidate policy: None
BSR RP policy: None
Auto-RP Announce policy: None
Auto-RP Discovery policy: None
Anycast-RP 10.1.1.1 members:
192.168.1.1* 192.168.2.2
RP: 10.1.1.1*, (0), uptime: 00:00:58, expires: never,
priority: 0, RP-source: (local), group ranges:
224.0.0.0/4
it looked OK
Nexus-2# show ip pim rp
PIM RP Status Information for VRF "default"
BSR disabled
Auto-RP disabled
BSR RP Candidate policy: None
BSR RP policy: None
Auto-RP Announce policy: None
Auto-RP Discovery policy: None
Anycast-RP 10.1.1.1 members:
192.168.1.1 192.168.2.2*
RP: 10.1.1.1*, (0), uptime: 02:46:54, expires: never,
priority: 0, RP-source: (local), group ranges:
224.0.0.0/4
and it looked okay as well
we started MC streams and they went to RP1 and everything worked as planned
when we shut down RP1 nothing worked anymore, and no new MC-streams were possible
--then we found that above mentioned errors
NOW how can the system not checking and not displaying any relevant error information?
from the config lines:
ip pim anycast-rp 10.1.1.1 192.168.1.1
ip pim anycast-rp 10.1.1.1 192.168.2.2
every node has everything he needs to know to check
1.) if the local RP address is defined
2.) if he can see/reach the remote loopback address of the other anycast RP-nodes
so IMHO a mechanism which gives no show command telling that the mechanism is not working is not a usable implementation
for a productive environment.
In a production system you can neither trace packets nor debug, you rely on either show commands or MIBs to detect the
working state of a mechanism
with best regards
alexander marhold
