Cisco CRS-1 - Carrier Routing System Router Troubleshooting Manual page 255

Chapter 13 Troubleshooting Load Balancing
Other flows usually use a different egress interface, because the hask algorithm produces a different hash
value. For example, a second flow that is identical to the first one except for the destination port is
forwarded out a different interface, GigabitEthernet0/6/5/7:
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 23 ingress-interface gi0/6/5/4
Tue Sep 23 04:03:25.145 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 GigabitEthernet0/6/5/7
Prefix Len 32, traffic index 0, precedence routine (0)
via GigabitEthernet0/6/5/7
After the traffic counters stabilize, the display now shows that the ingress flow on
GigabitEthernet0/6/5/4 has doubled and that that traffic is distributed equally between two egress
interfaces, GigabitEthernet 0/6/5/5 and 0/6/5/7, as expected:
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
ARP
GigabitEthernet0/6/5/5
Protocol
IPV4_UNICAST
IPV4_MULTICAST
GigabitEthernet0/6/5/6
Protocol
IPV4_MULTICAST
GigabitEthernet0/6/5/7
Protocol
IPV4_UNICAST
IPV4_MULTICAST
In an actual system, there is much more live traffic, so to the extent possible, reduce existing traffic so
you can more easily view the test traffic. These results were obtained with a traffic generator that creates
TCP flows, but you can obtain similar results using the ping command. Just make sure that the ping
packets pass through the router with load balancing interfaces to reach the destination IP address.
OL-21483-02
Configuration Examples for Troubleshooting Load Balancing
Ingress
Bits/sec Pkts/sec
86000 192
0
0
Ingress
Bits/sec Pkts/sec
0
0
Ingress
Bits/sec Pkts/sec
0
Ingress
Bits/sec Pkts/sec
0
0
Cisco IOS XR Troubleshooting Guide for the Cisco CRS-1 Router
Egress
Bits/sec
0
0 0
0 0
Egress
Bits/sec
0 43000
0 0
Egress
Bits/sec
0 0
Egress
Bits/sec
0 43000
0 0
Pkts/sec
0
0
0
Pkts/sec
96
0
Pkts/sec
0
Pkts/sec
92
0
13-245