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Gre Tunnel on VRF BW issue, ASR920

Tonay.R
Level 1
Level 1

I am facing an issue and confused about the output. Configured GRE tunnel in a VRF and Tunnel IS UP with no Ping loss in Tunnel interface IP. But when I add a route or some BW then it started huge p2p loss and tunnel gets up/down and ping loss again. 

I dont know What I am missing or what can be the issue, I tried the same tunnel in Cisco ASR 1004 (no vrf) and working fine. 

-----My Device License and Model ----

License Level: advancedmetroipaccess
License Type: Permanent
Next reload license Level: advancedmetroipaccess

cisco ASR-920-12SZ-IM-CC (Freescale T1042) processor (revision 1.2 GHz) with 908379K/6147K bytes of memory.

Tunnel Config ------
interface Tunnel1
vrf forwarding MGNT
ip address 10.60.1.9 255.255.255.248
ip tcp adjust-mss 1460
tunnel source 103.1xx.251.2
tunnel destination 103.xx.44.1
tunnel vrf MGNT

prottoy396_0-1720157654313.png

 

5 Replies 5

I need more info 
the tunnel destination is reach via mgmt vrf RIB ?
how you config static route ?

MHM 

Yes tunnel destination is reahable via MGNT vrf RIB

Using static route to forward all to another router where INTERNET is connected. Using this route, tunnel destnation is reachable. And I have also verified that Tunnel p2p IP is in MGNT vrf as it supposed to be.

TonayR_0-1720253545509.png

 



I have configured BGP for routing.
show bgp vrf MGNT vpnv4 unicast summary

TonayR_1-1720253862519.png

 

OK, so there is default route via mgmt interface 
then you config BGP over tunnel, when you run bgp did you receive any prefix  103.xx.44.1? 
what happened here is following 
1- tunnel is UP use default route via mgmt to 103.xx.44.1
2- bgp is UP and advertise 103.xx.44.1
3- tunnel stop use default route and use prefix learn via bgp (longest match) 
so tunnel is reach via tunnel itself 

try use route-map IN filter prefix you learn from BGP 

MHM

ANY updates

MHM

ccieexpert
Level 3
Level 3

what are you most likely seeing is what is called "recursive routing" .

you need to make sure that tunnel source/destination are not routed over the tunnel.. Either add static routes for them, or filter them out in your BGP routing protocol.

https://www.cisco.com/c/en/us/support/docs/ip/enhanced-interior-gateway-routing-protocol-eigrp/22327-gre-flap.html

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