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Virtual LANs Overview 12-17
Virtual LANs 
Overview
Virtual LANs (vLANs) represent location-independent logical user groups. 
LAN Emulation allows you to create enterprise-wide vLANs that closely 
correspond to how your network and business actually function. The 
VCC-timeout
An LEC should release any Data-direct VCC 
that has not been used to transmit or receive 
any data frames for the length of the VCC 
timeout period. This parameter is only 
meaningful for SVC Data-direct VCCs.
None specified 20 minutes
Unlimited
Aging-time
The maximum time that an LEC will maintain 
an entry in its LE_ARP cache in the absence of 
a verification of that relationship
10 seconds
300 seconds
Unlimited
Forward-delay-
time
The maximum time that an LEC will maintain 
an entry for a non-local MAC address in its 
LE_ARP cache in the absence of a verification 
of that relationship, as long as the Topology 
Change flag is true. 
4 seconds
15 seconds
30 seconds
Expected LE_ARP 
Response-time
The maximum time that the LEC expects an 
LE_ARP request/response cycle to take. Used 
for retries and verifies.
1 second
1 second
30 seconds
Topology-
change-flag
Boolean indication that the LEC is using the 
Forward delay time instead of Aging time to 
age non-local entries in its LE_ARP cache.
N/A
N/A
N/A
Flush-timeout
Time limit to wait to receive a LE_FLUSH 
response after the request has been sent, 
before taking recovery action. 
1 second
4 seconds
4 seconds
Path-switching-
delay
The time since sending a frame to the BUS 
after which the LEC may assume that the 
frame has been either discarded or delivered 
to the recipient. May be used to bypass the 
Flush protocol. 
1 second
6 seconds
8 seconds
Connection-
completion-
timer
In Connection Establishment this is the time 
period in which data or a READY_IND 
message is expected from a Calling Party.
1 second
4 seconds
10 seconds
Maximum-
unknown-frame-
count
Maximum number of unknown frames sent 
to BUS during the time period 
Maximum-unknown-frame-time.
1 frame
1 frame
10 frames
Maximum-
unknown-frame-
time
Within the period of time defined by the 
Maximum-unknown-frame-time, a LEC will 
send no more than 
Maximum-unknown-frame-count frames to 
the BUS for a given unicast LAN destination.
1 second
1 second
60 seconds
Table 12-6   LEC Operational Parameters (continued)
Parameter
Description
Minimum
Default
Maximum
abtthgde.book  Page 17  Tuesday, June 23, 1998  10:29 AM