EIGRP Flap on DS3 link , no drop on WAN

[gajanangavli]

Hi,

I have configured new DS3 link as below.Also GRE tunnel build on it.EIGRP running between tunnel interfaces.

EIGRP is flapping every minute , i dont found any packet drop between 2 routers WAN interfaces, but ping stcuks for some time.

During this time EIGRP flaps.ISP dont found any issue in network.

int s4/0

ip add x.x.x.x

encapsulation ppp

dsu bandwidth 44210

scramble

crc 32

serial restart-delay 0

interface Tunnel155

  bandwidth 25000

ip address A.B.C.D

no ip redirects

no ip proxy-arp

ip tcp adjust-mss 1432

load-interval 30

delay 100

qos pre-classify

keepalive 10 3

tunnel source Serial4/0

tunnel destination YY.Y.Y.

[Raju Sekharan]

Hi

Can you paste the logs you are getting

and paste the ping results

[gajanangavli]

HI,

Logs are as below.

%DUAL-5-NBRCHANGE: EIGRP-IPv4 888: Neighbor X.X.X.X (Tunnel155) is down: retry limit exceeded

%DUAL-5-NBRCHANGE: EIGRP-IPv4 888: Neighbor X.X.X.X (Tunnel155) is up: new adjacency

Ping response dont have any drop , but when ping observed closely , ping stucks at some point & eigrp flaps at that point.ping completes without drop.

[skarthic · Accepted solution]

Did you check the IP MTU on both sides of the tunnel? You might want to reduce the MTU size according to how much your physical link supports.

[Raju Sekharan]

What is the logs on other end

and interface configs

check the ping with the configured MTU with df-bit set and see if you are seeing any drops

[gajanangavli]

Hi Subramaniya/Raj,

After changing the MTU on tunnel interface , this issue got resolved.

Thanks For your help