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Document ID: 29460
Contents
Introduction
Prerequisites
Requirements
Components Used
Conventions
BXM Port Groups
Configuring Partitions
Checking LCN Allocation
Disabling a VSI Partition
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Introduction
Logical Connection Number (LCN) is a term given to an individual channel resource on a Broadband Switch Module (BXM) interface. LCN resources are shared between Autoroute and VSI (Virtual Switch Interface) using partitions.
LCN resources are configured by specifying a minimum and a maximum value. Only the number of LCNs are allocated to a partition and not a specific LCN range. The minimum LCN count is guaranteed for a partition, while an interface may use up to the maximum LCN count if it is available.
Prerequisites
Requirements
There are no specific requirements for this document.
Components Used
This document is not restricted to specific software and hardware versions.
The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.
Conventions
For more information on document conventions, refer to the Cisco Technical Tips Conventions.
BXM Port Groups
A port group is a set of interfaces that share the same LCN resources. The port groups on a BXM can be displayed by issuing the dspcd slot# command. The example below shows that this is an eight-port OC3 BXM. It has 16320 LCNs available and they are shared between two port groups.
STBPX-1 TN Cisco BPX 8620 9.3.11 Dec. 12 2002 09:00 GMT
Detailed Card Display for BXM-155 in slot 1
Status: Active
Revision: FDL Backcard Installed
Serial Number: 687272 Type: LM-BXM
Top Asm Number: 28215802 Revision: BB
Queue Size: 228300 Serial Number: 706939
Support: 8 Pts, OC3, FST, VcShp Supp: 8 Pts,OC3,MMF,RedSlot:NO
Supp: VT,ChStLv 1,VSI(Lv 3,ITSM)
Support: APS(FW)
Support: LMIv 1,ILMIv 1,NbrDisc
Support: OAMLp, TrfcGen
#Ch:16320,PG[1]:8160,PG[2]:8160
!--- This is the amount of LCNs.
PG[1]:1,2,3,4,PG[2]:5,6,7,8,
!--- These are the port groups.
#Sched_Ch:16384
Last Command: dspcd 1
Configuring Partitions
When a port or a trunk is first created, the default LCN allocation for Autoroute is 256. At this point, no allocation is given to VSI. The Autoroute LCN allocation is increased and VSI partitions are configured by issuing the cnfrsrc slot#.port# command.
STBPX-2 TN StrataCom BPX 8620 9.3.11 Dec. 12 2002 09:00 GMT
Port/Trunk : 1.2
Maximum PVC LCNS: 256 Maximum PVC Bandwidth:252207
(Statistical Reserve: 1000)
Partition 1
Partition State : Enabled
Minimum VSI LCNS: 1000
Maximum VSI LCNS: 4000
Start VSI VPI: 200
End VSI VPI : 400
Minimum VSI Bandwidth : 50000 Maximum VSI Bandwidth : 100000
VSI ILMI Config : 0
Last Command: cnfrsrc 1.2 256 352207 y 1 e 1000 4000 200 400 50000 100000
Allocate the number of LCNs to be used by a port group and not a specific range. To ensure that Autoroute does not use the same LCN as a VSI partition, Autoroute starts allocating LCNs from the bottom of the range and VSI allocates from the top. If you assume a port group has 4000 LCNs, the VSI partition starts using LCNs from the top 3999 and goes down, while Autoroute starts from LCN 0 and goes up.
Checking LCN Allocation
LCN resources in a BXM/UXM card can be checked by issuing the dspchuse slot# command.
STBPX-2 TN Cisco BPX 8620 9.3.11 Dec. 12 2002 09:00 GMT
Channel Management Summary for Slot 1
max used avail netw pvc cnfg vsi mgmt vsi cnf
card 1: 16320 8067 8253 542 1024 1 6500
port grp 1: 8160 8066 94 542 1024 0 6500
port grp 2: 8160 0 8160 0 0 0 0
pvc cnfg pvc used nw used vsi mgmt vsi min vsi max
phy if 1: 256 0 271 0
phy trk: 256 0
part 1: 1000 4000
part 2: 1000 4000
phy if 2: 256 0 271 0
phy trk: 256 0
part 1: 1000 4000
part 2: 1000 4000
phy if 3: 256 0 0 0
phy port: 256 0 0
part 1: 1000 6500
phy if 4: 256 0 0 0
phy port: 256 0 0
part 1: 500 1000
phy if 5: 0 0 0 0
This Command: dspchuse 1
Disabling a VSI Partition
The number of LCNs allocated to VSI on a port group cannot be decreased because the BPX/IGX software does not keep track of the actual LCN usage. To disable a VSI partition, you have to ensure that the VSI LCN count on a port group does not decrease due to the disabling of a VSI partition.
The VSI LCN count is based on the maximum amount of LCNs allocated in a port group. In this example, a port group is made up of four interfaces (1.1, 1.2, 1.3, and 1.4). The LCNs are allocated as shown in the table below.
|
Port |
Partition |
Minimum |
Maximum |
|---|---|---|---|
|
1.1 |
1 |
1000 |
4000 |
|
1.1 |
2 |
3000 |
4000 |
|
1.2 |
1 |
Disabled |
Disabled |
|
1.2 |
2 |
2000 |
3000 |
|
1.3 |
1 |
1000 |
4000 |
|
1.3 |
2 |
Disabled |
Disabled |
|
1.4 |
1 |
Disabled |
Disabled |
|
1.4 |
2 |
Disabled |
Disabled |
To find the total VSI LCN count you have to do the following :
-
Find the sum of the minimum LCN count for all partitions in a port group. From the above example: SUM_OF_MIN = (1000+3000+2000+1000) = 6000.
-
Find the maximum requirement from the MAX LCN count for all partitions in the port group. From the above example: MAX_OF_MAX = (4000,4000,3000,4000) the highest maximum requirement being 4000.
-
The total VSI LCN count is based on which ever number is highest SUM_OF_MIN or MAX_OF_MAX in our example SUM_OF_MIN is the highest value, so 6000 is the total VSI LCN count for this port group.
Now try to disable Partition 2 on Interface 1.2 and the following error message will appear:
Last Command: cnfrsrc 1.2 256 50000 N y 2 d Increase MAX VSI LCNs on another active partn in same port grp to 6000 Next Command:
Since disabling this VSI partition reduces the VSI count for the port group to 4000, the command does not succeed. In order to successfully disable this partition you have to increase the MAX LCN count on another active partition in the same port group. For example, issuing the cnfrsrc slot#.port# command increases the Max LCN count on Port 1.1 Partition 1 up to 6000. Once this is done, the VSI count will remain unchanged at 6000, even if you disable Partition 2 on Interface 1.2 and hence, the disabling succeeds.
STBPX-2 TN StrataCom BPX 8620 9.2.41 Dec. 12 2002 09:00 GMT
Port/Trunk : 1.2
Maximum PVC LCNS: 256 Maximum PVC Bandwidth:50000
(Statistical Reserve: 1000)
Partition 2
Partition State : Disable
Last Command: cnfrsrc 1.2 256 50000 y 2 d
The dchuse slot# command can also be used to check the total LCN VSI count by checking the "vsi cnf" entry.
STBPX-2 TN Cisco BPX 8620 9.3.11 Dec. 12 2002 09:00 GMT
Channel Management Summary for Slot 1
max used avail netw pvc cnfg vsi mgmt vsi cnf
card 1: 16320 8067 8253 542 1024 1 6000
port grp 1: 8160 8066 94 542 1024 0 6000
port grp 2: 8160 0 8160 0 0 0 0
pvc cnfg pvc used nw used vsi mgmt vsi min vsi max
phy if 1: 256 0 271 0
phy trk: 256 0
part 1: 1000 6000
part 2: 3000 4000
phy if 2: 256 0 271 0
phy trk: 256 0
part 2: 2000 4000
phy if 3: 256 0 0 0
phy port: 256 0 0
part 1: 1000 4000
phy if 4: 256 0 0 0
phy port: 256 0 0 This Command: dspchuse 1
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| Updated: Apr 30, 2009 | Document ID: 29460 |