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Point-to-point link dying while traffic is going across

All,

<br />

<br />I have a point-to-point link between two sites. This link constantly has traffic going through it (it's a DR site), and we're replicating across the link. Sometimes (a lot this week), we "lose" connection to the other side. I've reported this to the provider, but they don't see anything in their switch.

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<br />Tech specs of the link:

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<br />L2 link across fiber connection to other site.

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<br />Our router (3745) connects to the providers switch. The providers switch connects into the cloud, and this is mirrored on the other side: switch to a Cisco 2811. The providers switches are 2950s.

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<br />I can get into the 3745 and ping the serial interface of the 2811 OR the LAN interface, and the link will come up. It seems like it's having to ARP for the address though because the first ping will timeout, but then it will start responding. I've replaced the cable on the other end, but haven't replaced the router. I don't have any mac addresses listed on the routers and the entry in the arp cache for that address exists. I've enabled tcp-keepalives-in and out on the main router (3745), but this hasn't helped.

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<br />Any ideas?

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<br />Thanks!

<br />

<br />John

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<br />

<br />1) P2P Link.jpg

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HTH, John *** Please rate all useful posts ***
1 REPLY
Hall of Fame Super Silver

Re: Point-to-point link dying while traffic is going across

Hello John,

what if you add a static ARP entry on the C3745 like

arp 192.168.1.1 2811-mac-address arpa

just to see if there is an ARP problem.

Another option to keep the link up is that of using an ip routing protocol like RIP just to have messages going on both directions every 30 seconds.

You can configure two loopback interfaces and advertise them over the link (RIP needs something to advertise or it will not send its packets).

Hope to help

Giuseppe

 

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