Juniper JUNOS OS 10.4 - FOR EX REV 1 Manual page 1668

Complete Software Guide for Junos
Requirements
Overview and Topology
1564
®
OS for EX Series Ethernet Switches, Release 10.4
This example describes how to create a redundant trunk group with a primary and a
secondary link:
Requirements on page 1564
Overview and Topology on page 1564
Disabling RSTP on Switches 1 and 2 on page 1566
Configuring Redundant Trunk Links on Switch 3 on page 1567
Verification on page 1568
This example uses the following hardware and software components:
Two EX Series distribution switches
One EX Series access switch
Junos OS Release 10.4 or later for EX Series switches
Before you configure the redundant trunk links network on the access and distribution
switches, be sure you have:
Configured interfaces ge-0/0/9 and ge-0/0/10 on the access switch, Switch 3, as
trunk interfaces. See "Configuring Gigabit Ethernet Interfaces (CLI Procedure)" on
page 1284.
Configured one trunk interface on each distribution switch, Switch 1 and Switch 2.
Connected the three switches as shown in the topology for this example (see Figure
40 on page 1566).
In a typical enterprise network comprised of distribution and access layers, a redundant
trunk link provides a simple solution for network recovery when a trunk interface goes
down. After a trunk interface failure, data traffic is routed to another trunk interface,
thereby keeping network convergence time to a minimum. This example shows the
configuration of a redundant trunk group, which includes one primary link (and its
interface) and one unspecified link (and its interface) that serves as the secondary link.
A second type of redundant trunk group, not illustrated in the example, consists of two
unspecified links (and their interfaces); in this case, neither of the links is primary. In this
second case, the software selects an active link by comparing the port numbers of the
two links and activating the link with the higher port number. For example, if the two link
interfaces use interfaces
ge-0/1/0
interface names, the final number is the port number.)
The two links in a redundant trunk group generally operate the same way, whether they
are configured as primary/unspecified or unspecified/unspecified. Data traffic initially
passes through the active link but is blocked on the inactive link. While data traffic is
blocked on the secondary link, note that Layer 2 control traffic is still permitted if the link
is active. For example, an LLDP session can be run between two switches on the secondary
link. If the active link either goes down or is disabled administratively, it broadcasts a list
and , the software activates
ge-0/1/1
Copyright © 2010, Juniper Networks, Inc.
(In the
ge-0/1/1.