In the example above, PC-A wants to communicate with PC-B. They are in different VLANs so the traffic will be routed via the RSM (default gateway for the PCs). The first packet will be sent by PC-A and routed by the RSM towards PC-B; a shortcut, PC-A -- PC-B, will be created and all subsequent packets will be Layer 3 switched by the MLS-SE (Supervisor=NFFC).
PC-A#ping 12.12.12.12
!-- pinging PC-B
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 12.12.12.12, timeout is 2 seconds:
!!!!!
SUCcess rate is 100 percent (5/5), round-trip min/avg/max = 1/3/4 ms
On the switch:
switch-MLS-SE (enable) show mls entry
Destination IP Source IP PRot DstPrt SrcPrt Destination Mac Vlan Port
--------------- --------------- ---- ------ ------ ----------------- ---- -----
MLS-RP 11.11.11.1:
11.11.11.11 12.12.12.12 ICMP - - 00-d0-58-43-9f-60 11 6/11
!-- As in the note above we have two shortcuts A-B and B-A
12.12.12.12 11.11.11.11 ICMP - - 00-00-0c-07-ac-01 12 6/12
switch-MLS-SE (enable)
switch-MLS-SE (enable) show mls
Multilayer switching enabled
!-- By default, MLS is enabled on the switch
Multilayer switching aging time = 256 seconds
Multilayer switching fast aging time = 0 seconds, packet threshold = 0
Current flow mask is Destination flow
Configured flow mask is Destination flow
Total packets switched = 8
!-- Five echos and five replies were sent; the first echo and reply went
!-- through the RSM and subsequent were Layer 3 switched, which gives us a total of
!-- eight Layer 3 switched packets and two shortcuts.
Active shortcuts = 2
Netflow Data EXPort disabled
Total packets exported = 0
MLS-RP IP MLS-RP ID XTAG MLS-RP MAC-Vlans
---------------- ------------ ---- ---------------------------------
11.11.11.1 00100b108800 2 00-10-0b-10-88-00 11-12
switch-MLS-SE (enable)
switch-MLS-SE (enable) show mls statistics rp
Total packets switched = 8
Active shortcuts = 2
Total packets exported= 0
Total switched
MLS-RP IP MLS-RP ID packets bytes
--------------- ------------ ---------- ------------
11.11.11.1 00100b108800 8 944
switch-MLS-SE (enable)
RSM-MLS-RP#sho mls rp
multilayer switching is globally enabled
mls id is 0010.0b10.8800
mls ip address 11.11.11.1
!-- IP address of MLS-RP
mls flow mask is destination-ip
number of domains configured for mls 1
vlan domain name: sales
current flow mask: destination-ip
current sequence number: 3150688457
current/maximum retry count: 0/10
current domain state: no-change
current/next global purge: false/false
current/next purge count: 0/0
domain uptime: 1d00h
keepalive timer expires in 8 seconds
retry timer not running
change timer not running
1 management interface(s) currently defined:
vlan 11 on Vlan11
2 mac-vlan(s) configured for multi-layer switching:
mac 0010.0b10.8800
vlan id(s)
11 12
!-- VLANs, interfaces participating in MLS
router currently aware of following 1 switch(es):
switch id 0050.d133.2bff
!-- MAC address of the MLS-SE
On the switch, MLS is enabled by default. There is no need to specify the MLS-RP IP address if it is the RSM. However, for an external router acting as the MLS-RP, we need to configure the switch with this IP address by using the following command:
set mls include
To configure the router, follow the steps below:
Enable MLS IP in global configuration:
Router(config)#mls rp ip
Assign a VTP domain on one MLS interface. The show vtp domain command on the switch provides the VTP domain name; our example is "sales":
Router(config-if)#mls rp vtp-domain sales
Enable MLS on the interface so that it can participate in the shortcut process:
Router(config-if)#mls rp ip
Specify a router interface as a management interface, allowing for the MLS-SE and MLS-RP to communicate using a multicast protocol (MLSP):
Router(config-if)#mls rp management-interface
MLS-RP (RSM)
Current configuration:
!
version 11.3
!
hostname RSM-MLS-RP
!
!
mls rp ip
!
!
interface Vlan11
ip address 11.11.11.1 255.255.255.0
mls rp vtp-domain sales
mls rp management-interface
mls rp ip
!
interface Vlan12
ip address 12.12.12.1 255.255.255.0
mls rp vtp-domain sales
mls rp ip
!
ip classless
!
!
!
line con 0
line aux 0
line vty 0 4
login
!
end