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Cisco 10000 Series Router Software Configuration Guide
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Chapter 22 Configuring Multilink Point-to-Point Protocol Connections
Multilink Point-to-Point Protocol
that is equal to the sum of the bandwidths of the component links. MLP also provides load balancing,
multivendor interoperability, packet fragmentation and reassembly, and increased redundancy. The
Cisco 10008 router implements the MLP specifications defined in RFC 1990.
MLP provides traffic load balancing over multiple wide-area network (WAN) links by sending packets
and packet fragments over the links of bundle members. The multiple links come up in response to a
defined load threshold. MLP mechanisms can calculate load on both inbound and outbound traffic, or on
either direction as needed for the traffic between specific sites. MLP provides bandwidth on demand and
reduces transmission latency across WAN links.
MLP allows packets to be fragmented and the fragments to be sent at the same time over multiple
point-to-point links to the same remote address. Large nonreal-time packets are multilink encapsulated
and fragmented into a small enough size to satisfy the delay requirements of real-time traffic. However,
the smaller real-time packets are not multilink encapsulated. Instead, MLP interleaving provides a
special transmit queue (priority queue) for these delay-sensitive packets to allow the packets to be sent
earlier than other packet flows. Real-time packets remain intact and MLP interleaving mechanisms send
the real-time packets between fragments of the larger nonreal-time packets. For more information about
link fragmentation and interleaving, see the “Fragmenting and Interleaving Real-Time and
Nonreal-Time Packets” chapter in the
Cisco 10000 Series Router Quality of Service Configuration
Guide
.
MLP can provide increased redundancy by allowing traffic to flow over the remaining member links
when a port fails. You can configure the member links on separate physical ports on the same line card
or on different line cards. If a port becomes unavailable, MLP directs traffic over the remaining member
links with minimal disruption to the traffic flow.
MLP mechanisms preserve packet ordering over an entire bundle, guaranteeing that network packets are
processed at the receiving system in the same order that they are logically transmitted.
Valid multilink interface values for MLP over serial or multi-VC MLP over ATM are from 1 to 9999
(Release 12.2(28)SB and later), or from 1 to 9999 and 65,536 to 2,147,483,647 (Release 12.2(31)SB2
and later). For example:
Router(config)#
interface multilink 8
The Cisco 10008 router supports the following MLP features:
•
MLP over Serial Interfaces, page 22-13
•
Single-VC MLP over ATM Virtual Circuits, page 22-15
•
Multi-VC MLP over ATM Virtual Circuits, page 22-16
•
MLP on LNS, page 22-18
•
MLPoE LAC Switching, page 22-24
•
MLPoE at PTA, page 22-25
Feature History for Multilink PPP
Cisco IOS Release
Description
Required PRE
12.0(23)SX
The MLP over Serial feature was introduced on the
Cisco 10000 series router.
PRE1
12.2(28)SB
The MLP over Serial, Single-VC MLP over ATM VCs, and
Multi-VC MLP over ATM VCs features were introduced
on the PRE2.
PRE2
