Multilink point-to-point protocol – Cisco 10000 User Manual
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Cisco 10000 Series Router Software Configuration Guide
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Chapter 19 Configuring Multilink Point-to-Point Protocol Connections
Multilink Point-to-Point Protocol
Multilink Point-to-Point Protocol
Multilink Point-to-Point Protocol (MLP) is used to combine multiple physical links into a single logical
connection or MLP bundle (see
). Using MLP, you can increase bandwidth and more easily
manage all of the circuits through a single interface. The MLP connection has a maximum bandwidth
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
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 19-12
•
Single-VC MLP over ATM Virtual Circuits, page 19-14
•
Multi-VC MLP over ATM Virtual Circuits, page 19-15
•
•
MLPoE LAC Switching, page 19-23
•