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10-11
Catalyst 2950 Desktop Switch Software Configuration Guide
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Chapter 10 Configuring LRE
Configuring LRE Ports
In any of these cases, rate selection obtains the optimal profile for your line conditions.
Note When an LRE link is lost for fewer than 25 seconds, the switch does not execute rate selection to
re-establish the link. The link is re-established at the profile used before link loss.
The switch chooses the appropriate profile for an LRE interface when it executes rate selection. If line
conditions of the LRE interface change, rate selection must be executed again.
Precedence
The rate selection feature can be applied at both the port level and at the switch level. Profiles and
sequences have a system-defined priority level that work with rate selection to determine the rate for a
port or the entire switch. Port sequences have the highest priority; that is, they take precedence over any
other profile or sequence. The priority levels, from highest to lowest, are as shown:
1. Port sequence: rate selection is enabled on the given port only with the given sequence.
2. Global sequence: rate selection is enabled for the entire switch with the given sequence.
3. Port profile: rate selection is enable for the given port only with the given profile.
4. Global profile: rate selection is enabled for the entire switch with the given profile.
See Table 10-1 for the list of profiles and Table 10-2 for the list of system-defined sequences. You can
also use IOS commands or CMS to define your own sequences.
Note If rate selection is disabled for a port, then profiles are used.
Profile Locking
You can also use rate selection as an installation tool to lock in a particular profile. In this case, you
execute rate selection only once at installation; afterwards, rate selection is never executed, even if one
of the four listed events occur. You use the config command in privileged EXEC mode to lock the profile
chosen by rate selection. (You can enter a special EXEC command to rerun rate selection on the
interfaces that have locked the profiles, as needed.)
An advantage to profile locking is that the convergence time during bootup is faster if a profile is locked
on an LRE port rather than having to go through a profile sequence.
Beginning in privileged EXEC mode, follow these steps to lock a profile in an LRE port that has rate
selection enabled:
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
interface LRE-interface Enter interface configuration mode, and enter the number of the LRE port to
be configured.
Step 3
rate selection profile lock Lock the profile.
Step 4
end Return to privileged EXEC mode.
Step 5
show controllers lre profile details Verify the change.