DLSw+ and MSFC Frequently Asked Questions

Questions

Q1. Is DLSw+ supported on the MSFC/MSFC2 and what feature set is required to run DLSw+ on MSFC/MSFC2 in the Catalyst 6500?
Q2. What is the minimum IOS level that supports DLSw+ on the MSFC and what caveats should I be aware of when running DLSw+ on the MSFC/MSFC2 in general ?
Q3. How does DLSw+ Ethernet Redundancy work and what is it intended for ?
Q4. Is DLSw+ Ethernet Redundancy supported on the MSFC and with what kind of software do I need ?
Q5. Are there any disadvantages in running DLSw+ on the MSFC ?
Q6. Are there any performance figures to allow me to compare MSFC against other platforms for DLSw+ with TCP ?
Q7. Is DLSw+ FST encapsulation supported on the MSFC or MSFC2 ?
Q8. Can I configure DLSw+ on two MSFC cards in the same chassis ?
Q9. Where can I find a sample config for DLSw+ Ethernet Redundancy setup using MSFCs ?

Q1. Is Data Link Switching+ (DLSw+) supported on the Multilayer Switch Feature Card MSFC/MSFC2 and what feature set is required to run DLSw+ on MSFC/MSFC2 in the Catalyst 6500?

Yes, DLSw+ is supported on MSFC/MSFC2. The minimum feature set required for MSFC/MSFC2 is IP Plus. For MSFC the image name should read c6msfc-is-mz.xxx and for MSFC2 the image should read c6msfc2-is-mz.xxx, where xxx is the Cisco IOS® software version. It's highly recommended that you use the latest release available to registered users.

Q2. What is the minimum Cisco IOS level that supports DLSw+ on the MSFC and what caveats should I be aware of when running DLSw+ on the MSFC/MSFC2 in general?

The minimum Cisco IOS release that supports DLSw+ on the MSFC and MSFC2 is 12.1(1)E and 12.1(2)E respectively. However, due to some well known caveats, see below, it's important that the latest Cisco IOS release is used.

CSCds55205: DLSw+ does not work with MSFC2. Integrated in 12.1(04.04)EC and 12.1(04.04)E.

CSCds70377: DLSw+ Ethernet Redundancy does not work on MSFC2. Integrated in 12.1(05.06)EC and 12.1(05.06)E.

CSCdu13015, CSCdr65433, CSCdu30359: DLSw+ cause memory corruption on MSFC2. Integrated in 12.1(08a)E and 12.1(08.05)E.

CSCdp94760: DLSw+ Ethernet redundancy does not load balance between peers. Integrated in: 12.1(03)DC, 12.1(03)DB, 012.001(002.002), 12.1(02.02)T, 12.1(02.02)PI, and 12.1(02.03)E.

CSCdt14719: DLSw+ Ethernet redundancy needs more modularity to support better multiple instances. Integrated in 12.2(03.04)PB, 12.1(06.05)E, 12.2(00.18)S, 12.1(06.05)EC, 12.2(00.10)PI01, 12.1(06.05)AA, 012.002(000.010), 12.2(00.09)T, and 012.001(006.005).

The following apply to DLSw FST in general:

CSCdv07492: DLSw FST from ethernet to token ring always sets lf 516 integrated in 12.2(05.01)S and 12.1(10.3).

CSCdu34139: DLSw FST bridging from ISL sub-int does not work, integrated in 12.2(03.06)B, 12.2(04.01)S, 12.2(03.06)PB, 12.2(03.06)T, and 012.002(003.006).

Q3. How does DLSw+ Ethernet Redundancy work and what is it intended for?

DLSw+ Ethernet Redundancy feature was introduced in release 12.0(5)T to provide redundancy and load balancing between multiple DLSw+ peers in an Ethernet environment. The feature also enables DLSw+ to support multiple DLSw+ routers on the same transparent bridged domain that can reach the same MAC address in a switched environment. DLSw+ ethernet redundancy was designed for the remote branch office side, not the central site hub-end. For more information on DLSw+ Ethernet Redundancy see:

DLSw+ Ethernet Redundancy Sample Configuration

DLSw+ Ethernet Redundancy Feature

Q4. Is DLSw+ Ethernet Redundancy supported on the MSFC and with what kind of software do I need?

Yes, DLSw+ Ethernet Redundancy is supported on the MSFC, see Q2 for bugs you should be aware of. Minimum IP PLUS feature is also required see also Q1.

Q5. Are there any disadvantages in running DLSw+ on the MSFC ?

Yes, since the Catalyst 6500 does not support Token Ring, and Ethernet does not support RIF, DLSw+ has no way of knowing whether end-station device MAC addresses are sourced locally or remotely. This can result in major problems with bridge loops which can cause major SNA session disruption. DLSw+ is also process intensive; running any significant volume of DLSw traffic on the MSFC will be counterproductive to the real purpose of a Layer 3 switch. You've got much greater granularity in router CPU power, granularity, and scalability, for example, with 7200 NPE/NSE to handle workload and failover redundancy requirements than with the MSFC.

Note: You can run DLSw+ on an external router with a ISL sub-interfaces instead of running DLSw+ on the MSFC.

Q6. Are there any performance figures to allow me to compare MSFC against other platforms for DLSw+ with TCP?

Yes, there is a white paper on DLSw+ TCP Performance which shows percentage of the CPU utilized on various Cisco router platforms as a function of data frames transported between two Data-Link Switching Plus (DLSw+) TCP peers.

Q7. Is DLSw+ FST encapsulation supported on the MSFC or MSFC2?

Yes, FST is supported on the MSFC from 12.1(8.5)E2 as per ddts CSCdu47920 and from 12.1(9.5)E for MSFC2 as per ddts CSCdu47927.

Q8. Can I configure DLSw+ on two MSFC2 cards in the same chassis ?

DLSw+ on an MSFC works, however there has been no official testing done with two MSFC2s in the same chassis. DLSw+ code has no way of knowing that the two MSFC2s are in the same chassis, and has no supporting code for anything like this. More importantly, DLSw+ Ethernet Redundancy is designed for the remote end, not the central site. Ethernet Redundancy still assumes a Token Ring on the central location.

Q9. Where can I find a sample config for DLSw+ Ethernet Redundancy setup using an MSFC?

Consider the following topology:

Note: MSFC2 and Router2 are DLSw+ ethernet redundancy peers. Also note that the above setup was done in a lab environment with Ethernet media used for WAN connections. In reality this would done via serial connections.

Router1

!

hostname Router1
!
!
source-bridge ring-group 100
dlsw local-peer peer-id 172.17.240.68 promiscuous
!
!
interface Ethernet0/0
?description ip address 172.17.240.68 255.255.255.0
?ip address 172.17.240.68 255.255.255.0
?ip directed-broadcast
?half-duplex
!
!
interface TokenRing0/0
?no ip address
?ip directed-broadcast
?no keepalive
?ring-speed 16
?source-bridge 2 1 100
?source-bridge spanning
!

MSFC2:

!
hostname MSFC2
!
dlsw local-peer peer-id 172.17.240.4
dlsw remote-peer 0 tcp 172.17.240.68
dlsw transparent switch-support
!
!
interface Vlan1
 ip address 172.17.240.4 255.255.255.0
!
interface Vlan2
 mac-address 0222.0222.0222
 no ip address
 dlsw transparent redundancy-enable 9999.9999.9999 
!-- This router is Slave.
 dlsw transparent map local-mac 0220.0220.0220  remote-mac aaaa.aaaa.aaaa neighbor 0211.0211.0211
!

Router2:

!

hostname Router2
!
!
source-bridge ring-group 100
dlsw local-peer peer-id 172.17.240.40
dlsw remote-peer 0 tcp 172.17.240.68
dlsw transparent switch-support
!
!
interface Ethernet0
 description ip address 172.17.240.40 255.255.255.0
 ip address 172.17.240.40 255.255.255.0
 media-type 10BaseT
!
interface Ethernet1
 mac-address 0211.0211.0211
 no ip address
 keepalive 30
 media-type 10BaseT
 dlsw transparent redundancy-enable 9999.9999.9999 master-priority 10 
!-- This router is Master.
 dlsw transparent map local-mac 0201.0201.0201  remote-mac aaaa.aaaa.aaaa neighbor 0222.0222.0222
!

Verifications

MSFC2#show dlsw peer

Peers:??????????????? state???? pkts_rx?? pkts_tx? type? drops ckts TCP?? uptime
?TCP 172.17.240.68?? CONNECT????????? 8???????? 5? conf????? 0??? 0?? 0 00:02:00
Total number of connected peers: 1
Total number of connections:???? 1

MSFC2#
MSFC2#show dlsw transparent neighbor
Interface Vlan2
??? 4044.4044.4044? SELF???????????????????? Slave
 !-- Note: All mac addresses show non-cannonical format (Token Ring format).
??? 4088.4088.4088? Connected??????????????? MASTER.


MSFC2#show dlsw transparent map?
Interface Vlan2

????? LOCAL Mac????????? REMOTE MAC????? BACKUP
????? ---------????????? ----------????? ------
??? 4004.4004.4004???? 5555.5555.5555??? 4088.4088.4088???? STATIC?
??? 4080.4080.4080???? 5555.5555.5555??? 4088.4088.4088???? DYNAMIC(Passive)

Note: All mac addresses above are in non-cannonical format so we have Local Mac 4004.4004.4004 ( 0220.0220.0220 ) maps to the host mac address 5555.5555.5555 and 4088.4088.4088 being backup ( 0211.0211.0211 ) which is the other redundant DLSw peer ( Router2). Also note that the Client is configured to connect to 0201.0201.0201 in Router2 (alternatively it can point to MSFC2 0220.0220.0220 ), and not the host mac address of 5555.5555.5555. When Router2 sees the connection request to 0201.0201.0201 which is 4080.4080.4080 after bitswapping, Router2 maps this request to the host mac address 5555.5555.5555 as per the following configured command on Router2:

dlsw transparent map local-mac 0201.0201.0201 remote-mac aaaa.aaaa.aaaa neighbor 0222.0222.0222
!-- aaaa.aaaa.aaaa is the host mac address ( 5555.5555.5555 ) in cannonical format.

Note: All mac addresses in the above command are in cannonical format ( Ethernet format ).

MSFC2#show dlsw transparent cache?
Interface Vlan2
?Circuit Cache
local addr(lsap)??? remote addr(dsap)? state????????? Owner

Router1 has two peer connections:

Router1#show dlsw peer
Peers:??????????????? state???? pkts_rx?? pkts_tx? type? drops ckts TCP?? uptime
?TCP 172.17.240.40?? CONNECT????????? 9???????? 7? prom????? 0??? 1?? 0 00:00:17
?TCP 172.17.240.4??? CONNECT????????? 2???????? 2? prom????? 0??? 0?? 0 00:00:16
Total number of connected peers: 2
Total number of connections:???? 2

Router1#show dlsw reach
DLSw Local MAC address reachability cache list
Mac Addr???????? status???? Loc.??? port???????????????? rif
1000.5af2.f083?? FOUND????? LOCAL?? TokenRing0/0???? 06C0.0021.0640
5555.5555.5555?? FOUND????? LOCAL?? TokenRing0/0???? 0640.0641.0020

DLSw Remote MAC address reachability cache list
Mac Addr???????? status???? Loc.??? peer
0800.0800.0800?? FOUND????? REMOTE? 172.17.240.40(2065)
!-- 0800.0800.0800 is 1000.1000.1000 after bitswapping.

Router1#show dlsw circuit detail
Index?????????? local addr(lsap)??? remote addr(dsap)? state????????? uptime
4194304017????? 5555.5555.5555(08)? 0800.0800.0800(08) CONNECTED????? 00:00:15
??????? PCEP: 617BB7C4?? UCEP: 61AAB1BC
??????? Port:To0/0????????? peer 172.17.240.40(2065)
??????? Flow-Control-Tx? CW:20, Permitted:39; Rx CW:20, Granted:19; Op: Repeat
??????? Congestion: Low(02), Flow Op: Half: 0/0 Reset 0/0
??????? RIF = 0610.0641.0020
??????? Bytes:????????????? 18/129??????? Info-frames:?????????? 1/1?????????
??????? XID-frames:????????? 1/2????????? UInfo-frames:????????? 0/0?????????
Total number of circuits connected: 1

Router2#show dlsw transparent neighbor?
Interface Et1
??? 4088.4088.4088? SELF???????????????????? Master
??? 4044.4044.4044? Rcvd Master-Accepted???? VALID

Router2#sh dlsw transparent neighbor?
Interface Et1
????? LOCAL Mac????????? REMOTE MAC????? BACKUP
????? ---------????????? ----------????? ------
??? 4080.4080.4080???? 5555.5555.5555??? 4044.4044.4044???? STATIC
??? 4004.4004.4004???? 5555.5555.5555??? 4044.4044.4044???? DYNAMIC(Passive)
Router2#
Router2#

Router2 is the MASTER and have the transparent cache:

Router2#show dlsw transparent cache?
Interface Et1
?Circuit Cache
local addr(lsap)??? remote addr(dsap)? state????????? Owner
0800.0800.0800(08)? 5555.5555.5555(08) POSITIVE??????? SELF
Total number of circuits in the Cache: 1

Router2#sh dlsw reach
DLSw Local MAC address reachability cache list
Mac Addr???????? status???? Loc.??? port???????????????? rif
0800.0800.0800?? FOUND????? LOCAL?? Ethernet1???? --no rif--
1000.5af2.f59e?? FOUND????? LOCAL?? TokenRing0???? 06B0.0011.0640

DLSw Remote MAC address reachability cache list
Mac Addr???????? status???? Loc.??? peer
1000.5af2.f083?? FOUND????? REMOTE? 172.17.240.68(2065)
5555.5555.5555?? FOUND????? REMOTE? 172.17.240.68(2065) max-lf(8144)

Router2#sh dlsw peer
Peers:??????????????? state???? pkts_rx?? pkts_tx? type? drops ckts TCP?? uptime
?TCP 172.17.240.68?? CONNECT???????? 19??????? 17? conf????? 0??? 1?? 0 00:03:42
Total number of connected peers: 1
Total number of connections:???? 1

Router2#
Router2#sh dlsw circuit detail
Index?????????? local addr(lsap)??? remote addr(dsap)? state????????? uptime
1006632966????? 0800.0800.0800(08)? 5555.5555.5555(08) CONNECTED????? 00:03:41
??????? PCEP: 617880DC?? UCEP: 619DEFD8
??????? Port:Et1????????? peer 172.17.240.68(2065)
??????? Flow-Control-Tx? CW:20, Permitted:19; Rx CW:20, Granted:39; Op: Repeat
??????? Congestion: Low(02), Flow Op: Half: 0/0 Reset 0/0
??????? RIF = --no rif--
??????? Bytes:???????????? 129/18???????? Info-frames:?????????? 1/1?????????
??????? XID-frames:????????? 2/1????????? UInfo-frames:????????? 0/0?????????
Total number of circuits connected: 1

Router2#

Related Information

Updated: Jan 13, 2003

Document ID: 12352