Goal: to verify the path from CE11A to CE12A.
CE11A
sh ip route
verify 10.1.12.49
next hop = 150.1.11.18
verify route to 150.1.11.18
connected s1/0.101
sh cdp neighbor detail
verify the PE11 has 150.1.11.18 on S1/0.101
PE11
Is there a route to the target?
sh ip route
should show core routes only, no route to target
Are there any VPNs defined?
sh ip vrf
should show A and B
Which vrf is cust connected to?
how do you know? (S1/0.101 associated with vrf A)
Does vrf A have a route to 10.1.12.49?
sh ip route vrf A
verify route to 10.1.12.49
next hop should be egress PE router (192.168.1.33), no int!
Is there a path to the next hop?
sh ip route (global routing table)
for 192.168.1.33, next hop: 192.168.1.50, int S1/0.111
Is that int running MPLS?
sh mpls interface
Which VPN(s) (route target(s)) are associated with vrf A?
What VPN label is associated with the target?
sh ip bgp vpnv4 vrf A 10.1.12.49
should see: Extended community: RT:65001:10
mpls labels in/out nolabel/23
so label 23 is imposed as the VPN label
How is pkt sent to 192.168.1.33? (MPLS)
What label(s) are imposed on the pkt?
sh mpls forwarding-table (for 192.168.1.33, impose label 18)
Who is connectedto S1/0.111?
sh cdp neighbors (P11)
P11
Does P11 have a route to ultimate target (10.1.12.49)? (no – P11 uses MPLS)
sh ip route to verify
Does P11 have a route to 192.168.1.33 (egress PE)?
(yes, via 192.168.1.114, S1/0.112)
Does that interface run MPLS?
sh mpls interfaces (yes)
What does MPLS do with the packet?
sh mpls forwarding-table (has label of 18, swaps to label 17, forwards out S1/0.112)
Who is connected to S1/0.112?
sh cdp neighbor (P12)
P12
Does P12 have a route to the ultimate target? (no, MPLS)
sh ip route
Does P12 have a route to 192.168.1.33?
(yes via 192.168.1.65, S1/0.111)
Does that interface run MPLS
sh mpls interfaces (yes)
What does MPLS do with the packet?
sh mpls forwarding-table (has label of 17, pops label, forwards out S1/0.111)
Who is connected to S1/0.111?
sh cd neighbor (PE12)
PE12
Does PE12 have a route to the ultimate target?
sh ip route (no: global table has no customer routes)
PE12 is egress router for customer A
Does PE12 have vrf A implemented?
sh ip route vrf A (yes!)
Does vrf A have a route to the ultimate target (10.1.12.49)?
(yes! via 150.1.12.17, S1/0.101)
Is the VPN tag removed here?
sh ip bgp vpnv4 vrf A 10.1.12.49
refer to last line. You should see 23/nolabel
Is egress interface MPLS? (No)
Who is connected so S1/0.101?
sh cdp neighbor (CE12A)
CE12A
Does CE12A have a route to ultimate target (10.1.12.49)?
sh ip route (yes! direct via Loopback 0)
