How do I bundle 4xE1 into 1 Link?

[bericaleb]

Hi Experts

I have 4xE1 links between two sites. 2 are terminated between two routers and the other 2 are termianted on the other 2 routers. These E1 links are for our backup to a 100Mbps Microwave primary link. I'd like to make the 4xE1s to be 1 link. How can I do this?

[c.captari]

Hi. You have 2 options:

- use a routing protocol which supports multipath. Eigrp would be a good idea.

Second option: use multilink.

Multilink PPP, standardized in RFC 1990, is similar to load balancing techniques in that it sends packets across the individual links in a round robin fashion. However, Multilink PPP adds three significant capabilities:

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Since Multilink PPP works at the link layer, it makes an NxT1/E1 bundle appear as one logical link to the upper layer protocols in the router. Therefore, only one network address needs to be configured for the entire NxT1/E1 bundle.

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Multilink PPP keeps track of packet sequencing and buffers packets that arrive early. Multilink PPP preserves packet order across the entire NxT1/E1 bundle with this ability.

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You can enable packet fragmentation to split large data packets into smaller packet fragments that are individually transmitted across the links. In many circumstances, fragmentation can increase the efficiency of the NxT1/E1 link.

Reference: http://www.cisco.com/en/US/tech/tk713/tk628/technologies_configuration_example09186a00800a5efa.shtml

[bericaleb]

Hi Claudiu

Please see attached who the E1s are connected. How do I bundle them all into one link.

[lamav]

Hi

You can bundle 1 and 2 in an MLPPP bundle.

And in a separate bundle, do 3 and 4.

You cannot bundle all 4 together, as they reside on different routers.

HTH

Victor

[Joseph W. Doherty]

Cisco does provide a feature known as Multichassis Multilink PPP. I've never used it and since it was intended for access servers, unsure it could be used in your situation.

See http://www.cisco.com/en/US/products/hw/iad/ps417/products_configuration_guide_chapter09186a008007e1e6.html