Re: EIGRP Backdoor

No you don't need SoO because of the EIGRP metric encoding. SoO was only needed in older versions.

Brian McGahan, 4 x CCIE #8593 (R&S/SP/SC/DC), CCDE #2013::13
bmcgahan_at_INE.com<mailto:bmcgahan_at_INE.com>

Internetwork Expert, Inc.
http://www.INE.com<http://www.ine.com/>

On Nov 27, 2013, at 8:27 AM, "Mohammad Khalil" <eng_mssk_at_hotmail.com<mailto:eng_mssk_at_hotmail.com>> wrote:

Thanks Brian for the reply
What is not clear for me is
When I configure redistribution on both PE routers , I get the below

R3#sh ip route eigrp
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
       + - replicated route, % - next hop override

Gateway of last resort is not set

      4.0.0.0/32 is subnetted, 1 subnets
D 4.4.4.4 [90/158720] via 192.1.13.1, 00:01:02, FastEthernet1/0
D 192.1.24.0/24 [90/30720] via 192.1.13.1, 00:01:02, FastEthernet1/0

R3#ping 4.4.4.4 source lo0
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 4.4.4.4, timeout is 2 seconds:
Packet sent with a source address of 3.3.3.3
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 12/25/36 ms

R3#traceroute 4.4.4.4 source lo0 numeric
Type escape sequence to abort.
Tracing the route to 4.4.4.4
VRF info: (vrf in name/id, vrf out name/id)
  1 192.1.13.1 24 msec 8 msec 8 msec
  2 192.1.24.2 [MPLS: Label 18 Exp 0] 24 msec 16 msec 12 msec
  3 192.1.24.4 16 msec * 16 msec

R4#sh ip route eigrp
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
       + - replicated route, % - next hop override

Gateway of last resort is not set

      3.0.0.0/32 is subnetted, 1 subnets
D 3.3.3.3 [90/158720] via 192.1.24.2, 00:01:24, FastEthernet1/0
D 192.1.13.0/24 [90/30720] via 192.1.24.2, 00:01:24, FastEthernet1/0

R4#ping 3.3.3.3 source lo0
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
Packet sent with a source address of 4.4.4.4
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 16/24/32 ms

R4#traceroute 3.3.3.3 source lo0 numeric
Type escape sequence to abort.
Tracing the route to 3.3.3.3
VRF info: (vrf in name/id, vrf out name/id)
  1 192.1.24.2 12 msec 8 msec 4 msec
  2 192.1.13.1 [MPLS: Label 17 Exp 0] 12 msec 16 msec 20 msec
  3 192.1.13.3 24 msec * 16 msec

I have no loops taking place at the time , so do I really need to configure soo ?

And If I configured SOO ( as you can see above , am preferring the mpls backbone right now before applying soo)

R1,R2
route-map SOO_MAP permit 10
 set extcommunity soo 100:1
int f1/1
ip vrf sitemap SOO_MAP

R3#sh ip route eigrp

      4.0.0.0/32 is subnetted, 1 subnets
D 4.4.4.4 [90/2297856] via 192.1.34.4, 00:00:43, Serial2/0
D 192.1.24.0/24 [90/2172416] via 192.1.34.4, 00:00:43, Serial2/0

R4#sh ip route eigrp

      3.0.0.0/32 is subnetted, 1 subnets
D 3.3.3.3 [90/2297856] via 192.1.34.3, 00:01:37, Serial2/0
D 192.1.13.0/24 [90/2172416] via 192.1.34.3, 00:00:40, Serial2/0

So , the route is learned now via the backdoor link , and I want to keep learning it from the MPLS backbone

> From: bmcgahan_at_ine.com<mailto:bmcgahan_at_ine.com>
> To: eng_mssk_at_hotmail.com<mailto:eng_mssk_at_hotmail.com>; ccielab_at_groupstudy.com<mailto:ccielab_at_groupstudy.com>
> Date: Tue, 26 Nov 2013 17:10:49 -0600
> Subject: RE: EIGRP Backdoor
>
> If you want to learn the routes in the backdoor link then increase the delay
> on the CE link facing towards the PE. Changing the seed metric for EIGRP to
> VPNv4 BGP redistribution isn't going to affect anything, since the metrics
> from the EIGRP database are automatically copied in and overwrite whatever
> seed metric you set.
>
> The only time the seed metric matters is if the individual EIGRP vector
> metrics didn't get encoded in the VPNv4 update. This could happen because you
> have EIGRP on one side but a different protocol on the other side, if you do
> some sort of Inter-AS routing exchange that strips the extended communities
> that encoded the EIGRP vector metrics (e.g. Inter-AS Option A with IPv4
> Unicast EBGP as the PE to PE routing protocol) , or if you're running an older
> IOS version that didn't support the encoding to begin with.
>
> If you "show bgp vpnv4 unicast all x.y.w.z/len" on the PE router doing the
> redistribution you can see in the VPNv4 update what metrics have been set.
>
> Brian McGahan, 4 x CCIE #8593 (R&S/SP/SC/DC), CCDE #2013::13
> bmcgahan_at_INE.com<mailto:bmcgahan_at_INE.com><mailto:bmcgahan_at_INE.com>
>
> Internetwork Expert, Inc.
> http://www.INE.com<http://www.ine.com/>
>
> From: Mohammad Khalil [mailto:eng_mssk_at_hotmail.com]
> Sent: Tuesday, November 26, 2013 12:56 PM
> To: Brian McGahan; ccielab_at_groupstudy.com<mailto:ccielab_at_groupstudy.com>
> Subject: RE: EIGRP Backdoor
>
> OK if i wanted the routes to be learned through the backbone in this case what
> should i do? Increase the delay on the backdoor or should i change the eigrp
> seed metric when redistribution?
> Thanks
>
> > From: bmcgahan_at_ine.com<mailto:bmcgahan_at_ine.com><mailto:bmcgahan_at_ine.com>
> > To: eng_mssk_at_hotmail.com<mailto:eng_mssk_at_hotmail.com><mailto:eng_mssk_at_hotmail.com>;
> ccielab_at_groupstudy.com<mailto:ccielab_at_groupstudy.com><mailto:ccielab_at_groupstudy.com>
> > Date: Tue, 26 Nov 2013 10:04:38 -0600
> > Subject: RE: EIGRP Backdoor
> >
> > That's normal. Your metric of 1 1 1 1 1 doesn't apply because the EIGRP
> metric is automatically encoded into the VPNv4 BGP update, and then copied
> back into EIGRP when you redistribute it back on the other side. The SoO is
> normal too. By using the same value on the PE-CE links you're basically
> filtering those routes out.
> >
> > Brian McGahan, 4 x CCIE #8593 (R&S/SP/SC/DC), CCDE #2013::13
> > bmcgahan_at_INE.com<mailto:bmcgahan_at_INE.com><mailto:bmcgahan_at_INE.com>
> >
> > Internetwork Expert, Inc.
> > http://www.INE.com
> >
> >
> > -----Original Message-----
> > From: nobody_at_groupstudy.com<mailto:nobody_at_groupstudy.com><mailto:nobody_at_groupstudy.com>
> [mailto:nobody_at_groupstudy.com] On Behalf Of Mohammad Khalil
> > Sent: Tuesday, November 26, 2013 5:02 AM
> > To: ccielab_at_groupstudy.com<mailto:ccielab_at_groupstudy.com><mailto:ccielab_at_groupstudy.com>
> > Subject: EIGRP Backdoor
> >
> > Hi All
> > I have the below topology
> > R1 -- R2
> > | |
> > R3 -- R4
> >
> > All connections are FE except for the backdoor which is serial I have
> configured EIGRP as the PE-CE routing protocol between PE and CE (my PEs are
> R1 and R2) When I redistributed BGP into EIGRP I used a metric of 1 1 1 1 1 I
> see routes of My CEs through the MPLS backbone When I configured soo through
> the route-map and applied the ip vrf sitemap on the PE-CE interface , I see
> the routes now through the backdoor link , is that what suppose to happen or
> am missing something ?
> >
> > Thanks
> >
> >
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Received on Wed Nov 27 2013 - 10:27:32 ART