Redistribution ebgp to eigrp

[Steve Coady]

Hello

I have an AVPN network of 20 sites.5 of the sites are a recent acquisition

These 5 sites required a different default link to the internet and so a GRE tunnel was implemented between these 5 sites where the 0.0.0.0 is advertised across the GRE tunnel. BGP is used to advertise out the the AVPN cloud.

Sites_1-4 use site_5 as the internet link

These (5) sites currently use static routes but want to implement  EIGRP on their L3 HE switch & route amongst themselves

I need to redistribute eoigrp into bgp and possibly vice-versa.

Here is their proposed config:

Site_1 - 4 L3 switch EIGRP config

conf t

key chain KEY

key 1

key-string (string)

exit

conf t

int fa0/24

ip authentication mode eigrp 10 md5

ip authentication key-chain eigrp 10 KEY

exit

router eigrp 10

no auto-summary

eigrp stub connected static

network 10.0.0.0 0.255.255.255

network 172.16.0.0 0.0.240.255

network 192.168.0.0 0.0.255.255

Site_5 (Internet link) L3 switch Eigrp config

conf t

key chain KEY

key 1

key-string (string)

exit

conf t

int fa0/24

ip authentication mode eigrp 10 md5

ip authentication key-chain eigrp 10 KEY

exit

router eigrp 10

no auto-summary

network 10.0.0.0 0.255.255.255

network 172.16.0.0 0.0.240.255

network 192.168.0.0 0.0.255.255

Currently I have the WAN bgp configured specifying networks to be advertiised

router bgp 6xxxx

no bgp log-neighbor-changes

network 10.40.a.0 mask 255.255.255.0

network 10.40.b.0 mask 255.255.255.0

network 10.40.c.0 mask 255.255.255.0

network 10.40.d.0 mask 255.255.255.0

.

.

network 10.40.i.0 mask 255.255.255.0

redistribute static

neighbor 172.16.x.2 remote-as 11111

neighbor 172.16.x.2 distribute-list 10 in

Requirement:

I need specific statements to complete this redistribution

[Jon Marshall · Accepted solution]

Right then i can only think that the return traffic is going via the AVPN cloud. Which it is because i have just seen your last post.

One thing i forgot to ask.

You can if you want have sites 1 - 4 communicate with each other via the AVPN cloud. It is only site 5 that is the problem because site 5 has to know all subnets for the other new sites via the GRE tunnel.

Would you want this rather than all inter site traffic for the new sites going via GRE tunnels. ?

Jon

[Steve Coady]

Jon

"Would you want this rather than all inter site traffic for the new sites going via the AVPN cloud ?"

Is that Best practice?

[Jon Marshall · Accepted solution]

Steve

Apologies but i have just seen another issue. The GRE tunnel is on the same router as the BGP connection. Site 5 receives sites 1 - 4 routes via EIGRP which are AD 90 but it also sees sites 1 - 4 routes via BGP and because it's the same router it will always choose the AVPN cloud. So all return internet traffic will go via the AVPN cloud.

If this needs to be done tonight then it depends how quick and dirty you want it.  For example sites 1 - 4 already have a static route for internet.

At site 5 on the WAN router we could simply use static routes for all site 1 - 4's subnets pointing to the relevant GRE tunnel. Static routes are preferred over EBGP routes so that would work.  Statics are not the best because there is no failover ie. if site 1 tunnel went down it couldn't then use the AVPN cloud to get to sites 2 - 4. But how much traffic is there between the new sites if you take out internet connectivity ?

Note also that even if you used EIGRP and the tunnel went down you would still have sites 1 - 5 connectivity but no internet because we are not allowing the BGP default route in. So it all comes down to how much redundancy you want/need for sites 1 - 5 non internet connectivity ? 

Can you also confirm and this is important that each new site only has the one WAN router and that is the only entry/exit point into each site ?

Jon

[Steve Coady]

Jon

This is a production network for a newly acquired company. It has to be stable

The AVPN router is the only link to each site

Internet is critical as their customers access their services via the internet.

[Jon Marshall · Accepted solution]

Steve

My sincere apologies. Even though you told me it was one router i have stupidly been working under the assumption it was 2 routers connecting to a L3 switch. So i was concerned about EIGRP internal being preferred over EBGP but the actual issue is the other way round because it's all on the same router ie. the AVPN cloud will always be the preferred route.

And this happens at all new sites ie. BGP routes to new sites take preference over EIGRP learned routes. So here is what i propose -

1) let sites 1 - 4 use the AVPN cloud for inter site connectivity but not internet connectivity. This will happen without any extra config.

2) filter out the default route via BGP so sites 1 - 4 use the default route via the GRE tunnel.

3) site 5 is the issue. If we use EIGRP to advertise sites 1 - 4 subnets to site 5 down the GRE tunnel site 5 will ignore them and use the AVPN cloud. So we either -

i) change the admin distance of EIGRP at site 5 which is very messy but would mean that if the GRE tunnel went down for site 1 for example, site 5 could use the AVPN cloud for connectivity to site1 for non internet traffic. Site 1 has obviously lost connectivity to the internet.

or

ii) use statics on site 5 WAN router for all sites 1 - 4 subnets pointing to the relevant tunnel. Drawback here is that if tunnel to site 1 goes down teh AVPN cloud cannot be used as backup.

That said apart from internet just how much connectivity is there between the sites.

Once again i apologise for my really stupid mistake. 

If you want to carry on this (and i wouldn't blame you if you didn't) can you open a new thread where we can pick up as this thread is getting a bit long and taking a long time to load for me.

Let me know what you think.

Jon

[Steve Coady]

This sounds like the right path, what do I need to do?

" i) change the admin distance of EIGRP at site 5 which is very messy but  would mean that if the GRE tunnel went down for site 1 for example, site  5 could use the AVPN cloud for connectivity to site1 for non internet  traffic. Site 1 has obviously lost connectivity to the internet."

Are either of the (2) config I posted earlier of any use?

[Steve Coady]

"filter out the default route via BGP so sites 1 - 4 use the default route via the GRE tunnel"

I already have statically defined the default route acorss the tunnel so that takes prececdence over the default route via BGP, correct?

[Jon Marshall · Accepted solution]

Yes it does but not if we change to EIGRP.

Jon

[Jon Marshall · Accepted solution]

Steve

Are you the one implementing this. Can we do it one step at a time. The first thing to do is get EIGRP up and running between the new sites. Don't do anything with BGP yet and certainly don't do any redistribution anywhere.

So if you can do this step by step, simply get EIGRP running between all new sites. Leave the statics in at the moment.

I'm making the assumption that you do not want return traffic from the internet for the new sites going via the AVPN cloud ie.

site1 -> GRE tunnel -> site5 -> internet

internet -> site 5 -> AVPN cloud -> site 1

if that is acceptable then the config becomes a lot easier.

Oh and can you open new thread as this is getting difficult to follow.

Jon

[Steve Coady]

I am fine with internet traffic not going back across the AVPN tunnel

[Steve Coady]

Jon

You want me to enter the followijg at each sites?

router eigrp 10

no auto-summary

[Jon Marshall]

Steve

As long as there is no redistribution into BGP or into EIGRP.

I appreciate that you need to get this done but it is quite complex so it can't be rushed. What we need is to get EIGRP working between the new sites without doing any EIGRP -> BGP.

If return internet traffic has to go via the GRE tunnel then we need tp play around with EIGRP first. If return traffic went via the AVPN cloud then we wouldn't need to mess with the admin distance.

So start up EIGRP and get it running between the new sites. When you have done that give me a shout and we can look at the routing tables.

One other question. What does the internet connection connect to in site 5 ?

Jon

[Steve Coady]

Sorry I misunderstood/. Internet traffic going back across the AVPN is fine with me.

See new thrread      Redistribution EIGRP_2_BGP more

[Steve Coady]

I opened new thread called           Redistribution EIGRP_2_BGP more

[Steve Coady]

Jon

I apologize for the complexity.

I was advised yesterday that this had to happen and be installed by tonight.

Once again, i  appreciate your guidance