Using Cache Entries

Using Cache Entries
MLS entry or shortcut cache exists on the PFC for 6000 series switches. The purpose of the cache
is consistent across all platforms: The cache is a layer 3 switching table. It maintains the flow information
that facilitates MLS.
Here is a sample of a layer 3 cache table:
Terry_6509> (enable) show mls entry
Dest-IP Source-IP Prot DstPrt SrcPrt Dest-Mac Vlan
➥EDst ESrc DPort SPort Stat-Pkts Stat-Bytes Uptime Age
--------------- --------------- ----- ------ ------ ----------------- ----
➥---- ---- ------ ------ ---------- ----------- -------- --------
MSFC 10.10.100.5 (Module 15):
172.16.10.1 - - - - 00-30-96-2d-24-20 188
➥ARPA ARPA 2/7 2/6 870 157785 00:05:29 00:00:27
172.16.55.115 - - - - 00-30-96-2d-24-20 188
➥ARPA ARPA 2/7 2/6 2407 642886 00:00:39 00:00:00
172.16.96.101 - - - - 00-d0-bc-f3-69-44 4
➥ARPA ARPA 2/2 2/7 2710 2200670 00:12:23 00:00:00
172.16.8.35 - - - - 00-d0-bc-f3-66-9c 180
➥ARPA ARPA 3/7 3/3 76634 24951932 00:24:31 00:00:00
172.16.8.17 - - - - 00-30-96-2d-24-20 188
➥ARPA ARPA 2/7 2/6 81752 26599352 00:18:32 00:00:00
172.16.8.102 - - - - 00-30-96-2d-24-20 188
➥ARPA ARPA 2/7 2/6 313 148298 00:00:24 00:00:22
This command has many options, but the most basic ones involve viewing cache information
based on the source and destination IP addresses. The syntax of the command is show mls entry
[rp|destination|source] ip_address. Also, be aware that the display has room for many
pieces of information, but you won’t see them unless the flow is based on that information. For
example, when using the preceding Destination-IP flow, the source IP address isn’t displayed. You
will always be able to see the destination IP address and the destination MAC address.
Cache entries are kept while the flow is active. After the flow no longer receives traffic, the
cache entry gets aged out and removed from the layer 3 cache on the NFFC or PFC. This attribute
can be modified and adjusted. You’ll learn how to do that next.
A candidate entry is cached for five seconds to allow for an enable packet to arrive from the
router. If the enable packet doesn’t arrive in that time, the switch assumes that the best path is
not through itself and removes the entry.
Configuring the MLS Switch Engine