Platform Considerations - Juniper JUNOSE SOFTWARE FOR E SERIES 11.3.X - LINK LAYER CONFIGURATION GUIDE 2010-10-13 Configuration Manual

JunosE 11.3.x Link Layer Configuration Guide

Platform Considerations

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When you use hash-based link selection instead of the default round-robin link selection
for non-best-effort traffic, the router uses the IP source address (SA) and IP destination
address (DA) of the packet as a hash to select the MLPPP member link on which to
transmit the packet. Specifically, the router uses the hash algorithm to bind the
transmission of all traffic between this IP SA and IP DA to the same member link in the
MLPPP bundle.
If the member link selected to transmit high-priority packets becomes inoperable or is
removed from the MLPPP bundle, the router must select a different link on which to
transmit the packets. As a result, packets transmitted on this new link might sometimes
arrive at the remote destination before the traffic sent on the previously selected member
link.
You can configure hash-based MLPPP link selection in any of the following ways:
To configure hash-based link selection for a individual MLPPP member link, issue the
ppp hash-link-selection command from Interface Configuration mode or Subinterface
Configuration mode in the context of the individual link interface. For more information,
see "Configuring Static MLPPP" on page 308.
To configure hash-based link selection for all current member links in an MLPPP bundle,
issue the ppp hash-link-selection command from Interface Configuration mode in the
context of the MLPPP bundle. Doing this has the same effect as issuing the ppp
hash-link-selection command separately for each member link in the bundle. For more
information, see "Contextual Command Differences" on page 310.
To configure hash-based link selection for all dynamic MLPPP link interfaces created
by a profile, issue the ppp hash-link-selection command from Profile Configuration
mode. For more information, see "Configuring Dynamic MLPPP" on page 319.
For a detailed description and examples of using the ppp hash-link-selection command,
see "ppp hash-link-selection" on page 313.
You can configure MLPPP interfaces on the following E Series Broadband Services
Routers:
E120 router
E320 router
ERX1440 router
ERX1410 router
ERX710 router
ERX705 router
ERX310 router
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