Cisco CRS-1 - Carrier Routing System Router Troubleshooting Manual page 254

Configuration Examples for Troubleshooting Load Balancing
This shows that the CEF database does contain the three parallel links to 10.1.2.1 and shows the
associated hash bucket for each one. Therefore, CEF can correctly balance loads across these three
interfaces.
Verifying Load Balancing
Now you can verify that the flows are actually distributed among the parallel interfaces. The show cef
exact-route command displays the expected result of the hash calculation. If you are using the 3-tuple
configuration, you only need the required parameters. The protocol, source-port, destination-port, and
ingress-interface only apply to 7-tuple configurations.
In this example, a traffic generator is sending TCP packets to 10.1.2.1 from 192.168.254.1 through
interface Gi0/6/5/4. The source TCP port is 5500 and the destination port is 80. The following command
displays the calculated egress interface for this flow:
RP/0/RP0/CPU0:P2_CRS-8# show cef exact-route 192.168.254.1 10.1.2.1 protocol tcp
source-port 5500 destination-port 80 ingress-interface gi0/6/5/4
Tue Sep 23 03:17:36.339 PST DST
10.1.2.1/32, version 0, internal 0x40040001 (0xa9482f74) [1], 0x0 (0xa902a9cc), 0x4400
(0xa9db444c)
Updated Sep 19 11:52:34.493
remote adjacency to GigabitEthernet0/6/5/5
Prefix Len 32, traffic index 0, precedence routine (0)
via GigabitEthernet0/6/5/5
CEF load balancing sends this particular flow out of interface GigabitEthernet0/6/5/5. You can verify
that a flow with the specified characteristics is acutally using GigabitEthernet0/6/5/5 using the following
command:
RP/0/RP0/CPU0:P2_CRS-8# show interface accounting rates
Tue Sep 23 05:57:03.780 PST DST
GigabitEthernet0/6/5/4
Protocol
IPV4_UNICAST
IPV4_MULTICAST
GigabitEthernet0/6/5/5
Protocol
IPV4_UNICAST
IPV4_MULTICAST
GigabitEthernet0/6/5/6
Protocol
IPV4_MULTICAST
ARP
GigabitEthernet0/6/5/7
Protocol
IPV4_MULTICAST
This shows that the ingress data rate on GigabitEthernet0/6/5/4 is 43000 bps and that the egress data rate
on interface GigabitEthernet0/6/5/5 is also 43000 bps, as expected.
Cisco IOS XR Troubleshooting Guide for the Cisco CRS-1 Router
13-244
Ingress
Bits/sec Pkts/sec
43000
0
Ingress
Bits/sec Pkts/sec
0
0
Ingress
Bits/sec Pkts/sec
0
0
Ingress
Bits/sec Pkts/sec
0
Chapter 13 Troubleshooting Load Balancing
Egress
Bits/sec
95 0
0 0
Egress
Bits/sec
0 43000
0 0
Egress
Bits/sec
0 0
0 0
Egress
Bits/sec
0 0
Pkts/sec
0
0
Pkts/sec
92
0
Pkts/sec
0
0
Pkts/sec
0
OL-21483-02