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10-4
Catalyst 2950 Desktop Switch Software Configuration Guide
78-14982-01
Chapter10 Configuring LRE
LRE Links and LRE Profiles
• Use the LL profiles (LRE-5LL, LRE-10LL, and LRE-15LL) with care. These profiles have the
low-latency (LL) feature enabled and the interleaver feature disabled. The LL feature does not delay
data transmission, but it makes data more susceptible to interruptions on the LRE link.
All other profiles, port and global, have the interleaver feature enabled and the LL feature disabled.
The interleaver feature provides maximum protection against small interruptions on the LRE link
but delays data transmission.
• The symmetric profiles (LRE-5, LRE-10, LRE-15, LRE-8, LRE-7, LRE-4, LRE-3, and LRE-2)
provide full-duplex throughput on the link between the LRE switch and CPE device. Under ideal
conditions, this can mean up to 30 Mbps of bandwidth on the LRE link if you are using the LRE-15
profile.
LRE Sequences
The LRE switches are shipped with predefined sequences. Sequences are sets of profiles and are used in
conjunction with the rate selection feature. The rate selection feature enables the switch to automatically
select profiles. You can also define your own sets of sequences using IOS commands or CMS. See the
“Using Rate Selection to Automatically Assign Profiles” section on page 10-10 for further information.
Table 10-2 outlines the predefined sequences for rate selection contained in Cisco IOS. When executing
rate selection, the switch uses a sequences to choose an appropriate profile for a given LRE interface.
Table 10-2 LRE Rate Selection Sequences
LRE-SEQ-
COMPLETE-
REACH
LRE-SEQ-
DOWNSTREAM LRE-SEQ-SYM
LRE-SEQ-SYM-
LONGREACH
LRE-SEQ-
SYMLL
LRE-SEQ-
UPSTREAM
LRE-SEQ-
VIDEO-
TRANSMIT1
LRE-SEQ-
VIDEO-
TRANSMIT2
LRE-15 LRE-15 LRE-15 LRE-5 LRE-15LL LRE-15 LRE-15 LRE-15
LRE-10 LRE-15-5 LRE-10 LRE-4 LRE-10LL LRE-10 LRE-15-5 LRE-15-5
LRE-15-5 LRE-15-3 LRE-8 LRE-3 LRE-5LL LRE-8 LRE-15-3 LRE-10
LRE-10-5 LRE-15-1 LRE-7 LRE-2 LRE-7 LRE-15-1 LRE-10-5
LRE-8 LRE-10 LRE-5 LRE-4-1 LRE-15-5 LRE-10 LRE-15-3
LRE-7 LRE-10-5 LRE-4 LRE-10-5 LRE-10-5 LRE-10-3
LRE-15-3 LRE-10-3 LRE-3 LRE-5 LRE-10-3 LRE-15-1
LRE-10-3 LRE-10-1 LRE-2 LRE-4 LRE-10-1 LRE-10-1
LRE-5 LRE-8 LRE-15-3
LRE-15-1 LRE-7 LRE-10-3
LRE-10-1 LRE-5 LRE-3
LRE-4 LRE-4 LRE-2
LRE-3 LRE-4-1 LRE-4-1
LRE-2 LRE-3
LRE-4-1 LRE-2