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RE: MP vs. MMP [7:50198] posted 07/31/2002
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>Mann, Chris wrote:
>>  I am studying for the CID test and am a little fuzzy about what
>>  the main
>>  differences between MP(Multilink PPP)and MMP(Multilink
>>  Multichassis PPP).
>>  Don't they both combine ISDN B channels across multiple access
>>  servers or
>>  routers??
>No, only the second one combines channels across multiple access servers.
>Multilink PPP (MP) simply works to bring up both ISBN B channels on a single
>interface, for example.
>MP was the original enhancement to PPP that added support for basic channel
>aggregation. MP ensures that packets arrive in order at the receiving device
>through the use of sequence number. Multiple channels appear as one logical
>link to upper-layer protocols.
>Multichassis MP is a Cisco IOS enhancement to MP that allows channel
>aggregation across multiple remote-access servers at a central site.
>Multichassis MP allows you to group multiple access servers into a single
>stack group. User traffic can be split and reassembled across multiple
>access servers in the stack group.
>Multichassis MP makes use of the Stack Group Bidding Protocol (SGBP). SGBP
>defines a bidding process to allow access servers to elect a server to
>handle aggregation for an application. The server has the job of creating
>and managing a bundle of links for an application that requests channel
>So, anyway, it all boils down to that multichassis is multi in two ways:
>multiple chassis and multilink PPP. Also, multichassis requires SGBP. It
>really helps to look at a picture. Hopefully your study materials have a
>picture. It also helps to know the history and to realize that Cisco always
>has to add enhancements and bells & whistles to the basic concept. So MP
>came first. Then Cisco made it even more complicated with multichassis MP.

You haven't begun to get into complexity until you experience MLPPP 
over L2TP, the L2TP possibly running through IPsec.

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