| 5.6 | Optional Configuration | ||
| 5.6.3 | Multilink PPP |
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BOD has been further enhanced by basing its
implementation on industry-standard MLP. The MLP feature provides
load balancing over multiple WAN links, while providing multivendor
interoperability, packet fragmentation, proper sequencing, and load
calculation on both inbound and outbound traffic. As shown in Figure
PPP Multilink Terminology MLP-based BOD is available in Cisco IOS Release 11.0 and later, and it is available in Cisco 700 series routers with Release 3.2 and later. 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. The multiple links come up in response to a dialer load threshold that you define. The load can be calculated on inbound traffic, outbound traffic, or either, as needed for the traffic between the specific sites. MLP provides BOD and reduces transmission latency across WAN links. Use the dialer load-threshold load command, which has the keywords inbound, outbound, or either, for MLP-based BOD. For remote users, configure the load threshold outbound. Then, configure ppp multilink, which allows you to turn MLP on or off. This command is placed either on the physical interface or in a dialer interface, depending on the interface type, quantity of interfaces configured, and whether dialer rotary groups or dialer profiles are used. The following is an example of multilink activation:
The ppp multilink command can be configured on the following:
By default, both B channels of a BRI are in a two-link rotary group. PRIs can have up to 23 links per rotary group for T1 or 30 links for E1. Note: Click on the topology to view the
configuration of BRI 0 for MLP and the rotary group interface
configured for MLP.
Configuring Load Threshold Value In small offices, use the
either
option for load threshold to ensure that the maximum of the inbound and outbound traffic is calculated as the load threshold. As shown in Figure
PPP authentication plays a part in MLP. The bundle decision is based on the authentication name of the remote router independently on each side of the link. Each router should use a unique hostname for authentication, with a shared password. If authentication is not configured correctly, MLP will not work correctly. When single multilink BRIs or a rotary group
with multiple BRIs are calling a PRI, do not put a dialer
load-threshold on the PRI or multiple
BRI rotary group. Use the dialer
load-threshold command on the single
BRI interface. This will prevent attempts to bring up a third B
channel to a single BRI destination.
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