Cisco Cisco IOS Software Releases 12.2 MC

arriving out of order). The receiver must be capable of buffering enough data to compensate for normal 
slippage between the links, otherwise it will be incapable of completely sequencing and reassembling 
datagrams, and some data will be lost.

With Cisco IOS Release 12.2(15)MC1 and later, the MLP reorder buffer can be adjusted for cases where 
the slippage is larger than the defaults readily accommodate. The buffer size is set by defining a one or 
more constraints, each of which indirectly implies some byte limit. The limit used is the maximum of 
the value derived from the constraints.

To define the constraints that set the MLP reorder buffer size, issue the following commands while in 
interface configuration mode:

Note that these limits are on a “per-link” basis. For example, issuing ppp multilink slippage mru 4 
means that the total amount of data which is buffered by the bundle is 4 times the MRU times the number 
of links in the bundle.

The reassembly engine is also affected by the lost fragment timeout, which is configured using the 
ppp timeout multilink lost-fragment command.

The buffer limit derived from the slippage constraints implies a corresponding tolerated differential 
delay between the links. Since it does not make sense to be declaring a fragment lost due to a timeout 
when it is within the delay window defined by the slippage, the timeout will be dynamically increased 
as necessary so that it is never smaller than the delay value derived from the slippage parameters.

 

This section contains information that was not included or was documented incorrectly in the 
MGX-RPM-1FE-CP Back Card Installation and Configuration Note. The heading in this section 
corresponds with the applicable section title in the documentation.

Router(config-if)# ppp multilink slippage mru value

Specifies that the buffer limit is x bytes where the 
byte count is expressed as a multiple of the 
maximum receive unit (MRU) negotiated for the 
bundle (the buffer limit is derived as the number of 
times defined for the value times the size of the 
largest packet received). Valid values are 2 through 
32. The default is 8.

The MRU is dynamically negotiated with 
the peer when the connection is 
established, therefore, the byte count also 

Router(config-if)# ppp multilink slippage msec value

Specifies the buffer limit, in milliseconds worth of 
data. Valid range is 1 to 16000.

The actual amount of data buffered 
depends upon the bandwidth of the links.