Hi All,
If the PE router, in a Carrier's Carrier scenario has learnt about a /32 route via BGP and ISIS in the same time. For the BGP learnt route, the PE also has learnt a label via the BGP, and for the ISIS learnt route, LDP has allocated a label for it.
So the ending result it that:
PE5#show ip route 30.30.30.30
Routing entry for 30.30.30.30/32
Known via "isis", distance 115, metric 20, type level-2
Redistributing via isis
Last update from 172.12.12.1 on GigabitEthernet1/0, 00:03:17 ago
Routing Descriptor Blocks:
* 172.12.12.1, from 40.40.40.40, 00:03:17 ago, via GigabitEthernet1/0
Route metric is 20, traffic share count is 1
PE5#show mpls forwarding-table
Local Outgoing Prefix Bytes Label Outgoing Next Hop
Label Label or Tunnel Id Switched interface
23 18 10.10.10.10/32 0 Gi1/0 172.12.12.1
===
PE5#show ip bgp
BGP table version is 318, local router ID is 50.50.50.50
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, x best-external
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
r>i10.10.10.10/32 40.40.40.40 0 100 0 3 1 i
PE5#show ip bgp labels
Network Next Hop In label/Out label
10.10.10.10/32 40.40.40.40 nolabel/17
===
What label would the PE use to reach 10.10.10.10/32? Would it use the LDP allocated label which is 18 or the BGP learnt label which is 17?
Thank you.