I'm trying to understand the following -
Upon completion of this task If I look on both CEs (SW1/2) I can see lots of D routes via the MPLS cloud, which is the ultimate aim of the task. (SW1 uplink to R6(PE) is via Vlan67, SW2 uplink to R5(PE) is via Vlan58).
My question is, why are there still some EIGRP learnt routes via the backdoor, and not all via the MPLS cloud (like all the others)?
Excerpt from each CEs routing table:
SW1:
D 150.1.8.0/24 [90/156416] via 155.1.67.6, 00:09:10, Vlan67 <-- This network is Lo0 on SW2 (learnt from mpls cloud)
D 172.16.8.0/24 [90/409600] via 155.1.78.8, 03:00:17, FastEthernet0/15 <-- This network is Lo100 on SW2 (learnt from backdoor)
SW2:
D 155.1.7.0 [90/28672] via 155.1.58.5, 03:01:45, Vlan58 <-- This network is VLAN7 on SW1 (learnt from mpls cloud)
D 172.16.7.0/24 [90/409600] via 155.1.78.7, 03:01:45 <-- This network is Lo101 on SW1 (learnt from backdoor)
Lets take 172.16.8.0/24
On SW1:
SW1#sh ip ei top 172.16.8.0 255.255.255.0
IP-EIGRP (AS 100): Topology entry for 172.16.8.0/24
State is Passive, Query origin flag is 1, 1 Successor(s), FD is 409600
Routing Descriptor Blocks:
155.1.78.8 (FastEthernet0/15), from 155.1.78.8, Send flag is 0x0
Composite metric is (409600/128256), Route is Internal
Vector metric:
Minimum bandwidth is 100000 Kbit
Total delay is 15000 microseconds
Reliability is 255/255
Load is 1/255
Minimum MTU is 1500
Hop count is 1
So EIGRP only knows of the route via the backdoor. If I pull the backdoor link
SW1#sh ip ei top 172.16.8.0 255.255.255.0
% IP-EIGRP (AS 100): Route not in topology table
Ok odd - so I jump onto R6 (SW1s PE) and check that I have an EIGRP peering configured and up for VPN_A:
R6#sh ip ei vrf VPN_A nei
EIGRP-IPv4 VR(PE-CE) Address-Family Neighbors for AS(100)
VRF(VPN_A)
H Address Interface Hold Uptime SRTT RTO Q Seq
(sec) (ms) Cnt Num
0 155.1.67.7 Fa0/0.67 14 00:20:47 1 200 1 25351
Ok good, I do. Now I check to see that I have the route to 172.16.8.0/24 in my EIGRP topology database for VPN_A (this output is when the backdoor link on the CE is backup):
R6#sh ip ei vrf VPN_A top 172.16.8.0 255.255.255.0
EIGRP-IPv4 VR(PE-CE) Topology Entry for AS(100)/ID(150.1.66.66)
Topology(base) TID(0) VRF(VPN_A)
EIGRP-IPv4(100): Topology base(0) entry for 172.16.8.0/24
State is Passive, Query origin flag is 1, 1 Successor(s), FD is 156160
Descriptor Blocks:
150.1.5.5, from VPNv4 Sourced, Send flag is 0x0
Composite metric is (156160/0), route is Internal (VPNv4 Sourced)
Vector metric:
Minimum bandwidth is 100000 Kbit
Total delay is 5100 microseconds
Reliability is 255/255
Load is 1/255
Minimum MTU is 1500
Hop count is 1
155.1.67.7 (FastEthernet0/0.67), from 155.1.67.7, Send flag is 0x0
Composite metric is (412160/409600), route is Internal
Vector metric:
Minimum bandwidth is 100000 Kbit
Total delay is 15100 microseconds
Reliability is 255/255
Load is 1/255
Minimum MTU is 1500
Hop count is 2
Ok it's in the topology table - lets check the eigrp routing table:
R6#sh ip route vrf VPN_A ei | in 172.16.8.0
<ITS NOT THERE>
So I'm receiving it into R6 from R5 via the mpls cloud, but it's not being entered into the vrf RIB for VPN_A, on R6. As such, SW1 only knows about it via it's EIGRP peering via the backdoor link to SW2.
So the question is - why is this happening?
(if you look at the SG output, even that has routes in the CE that are still using the backdoor link...)
Would appreciate any assistance - scratching my head with this one! :)