also to follow up with the CEF you can see that pretty easy in this test,
check out the per-destination sharing vs per packet sharing when you send 4
ICMP echo requests from R2 loopback to R1 loopback interface, you can see
the per packet goes over each interface per ICMP packet and then it sticks
to s0/1 in the per-destination CEF setting:
R2#debug ip packet detail 101
IP packet debugging is on (detailed) for access list 101
R2#sh ip cef 100.100.100.100
100.100.100.100/32, version 27, epoch 0, per-packet sharing
R2#ping 100.100.100.100 r 4 source loopback 200
Type escape sequence to abort.
Sending 4, 100-byte ICMP Echos to 100.100.100.100, timeout is 2 seconds:
Packet sent with a source address of 200.200.200.200
!!!!
Success rate is 100 percent (4/4), round-trip min/avg/max = 8/56/80 ms
R2#
*Mar 1 00:22:53.339: IP: tableid=0, s=200.200.200.200 (local),
d=100.100.100.100 (FastEthernet0/1), routed via FIB
*Mar 1 00:22:53.339: IP: s=200.200.200.200 (local), d=100.100.100.100
(FastEthernet0/1), len 100, sending
*Mar 1 00:22:53.343: ICMP type=8, code=0
*Mar 1 00:22:53.415: IP: tableid=0, s=200.200.200.200 (local),
d=100.100.100.100 (FastEthernet0/0), routed via FIB
*Mar 1 00:22:53.415: IP: s=200.200.200.200 (local), d=100.100.100.100
(FastEthernet0/0), len 100, sending
*Mar 1 00:22:53.419: ICMP type=8, code=0
*Mar 1 00:22:53.479: IP: tableid=0, s=200.200.200.200 (local),
d=100.100.100.100 (Serial0/1), routed via FIB
*Mar 1 00:22:53.479: IP: s=200.200.200.200 (local), d=100.100.100.100
(Serial0/1), len 100, sending
*Mar 1 00:22:53.479: ICMP type=8, code=0
*Mar 1 00:22:53.487: IP: tableid=0, s=200.200.200.200 (local),
d=100.100.100.100 (Serial0/0), routed via FIB
*Mar 1 00:22:53.491: IP: s=200.200.200.200 (local), d=100.100.100.100
(Serial0/0), len 100, sending
*Mar 1 00:22:53.491: ICMP type=8, code=0
R2#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R2(config)#int f0/0
R2(config-if)#ip load-sharing per-destination
R2#clear ip route *
R2#sh ip cef 100.100.100.100
100.100.100.100/32, version 27, epoch 0, per-destination sharing
R2#ping 100.100.100.100 r 4 source loopback 200
Type escape sequence to abort.
Sending 4, 100-byte ICMP Echos to 100.100.100.100, timeout is 2 seconds:
Packet sent with a source address of 200.200.200.200
!!!!
Success rate is 100 percent (4/4), round-trip min/avg/max = 8/49/96 ms
R2#
*Mar 1 00:25:15.807: IP: tableid=0, s=200.200.200.200 (local),
d=100.100.100.100 (Serl0/1), routed via FIB
*Mar 1 00:25:15.807: IP: s=200.200.200.200 (local), d=100.100.100.100
(Serial0/1), le 100, sending
*Mar 1 00:25:15.811: ICMP type=8, code=0
*Mar 1 00:25:15.843: IP: tableid=0, s=200.200.200.200 (local),
d=100.100.100.100 (Ser l0/1), routed via FIB
*Mar 1 00:25:15.843: IP: s=200.200.200.200 (local), d=100.100.100.100
(Serial0/1), le 100, sending
*Mar 1 00:25:15.847: ICMP type=8, code=0
*Mar 1 00:25:15.939: IP: tableid=0, s=200.200.200.200 (local),
d=100.100.100.100 (Ser l0/1), routed via FIB
*Mar 1 00:25:15.943: IP: s=200.200.200.200 (local), d=100.100.100.100
(Serial0/1), le 100, sending
*Mar 1 00:25:15.943: ICMP type=8, code=0
*Mar 1 00:25:15.999: IP: tableid=0, s=200.200.200.200 (local),
d=100.100.100.100 (Ser l0/1), routed via FIB
*Mar 1 00:25:15.999: IP: s=200.200.200.200 (local), d=100.100.100.100
(Serial0/1), le 100, sending
-- Garry L. Baker "There is no 'patch' for stupidity." - www.sqlsecurity.com On Sat, Jul 31, 2010 at 12:35 PM, garry baker <baker.garry_at_gmail.com> wrote: > maybe some of this will get you going in the right direction... > > by default OSPF does equal cost load balancing: > > > http://www.cisco.com/en/US/tech/tk365/technologies_q_and_a_item09186a0080094704.shtml#q37 > > simple example to see it and also change the defaults to get into load > balance over "unequal cost" paths by making them equal: > R1#sh ip int br | e una > Interface IP-Address OK? Method Status > Protocol > FastEthernet0/0 1.1.1.1 YES manual up > up > Serial0/0 3.3.3.1 YES manual up > up > FastEthernet0/1 2.2.2.1 YES manual up > up > Serial0/1 4.4.4.1 YES manual up > up > Loopback100 100.100.100.100 YES manual up > up > > R2#sh ip int brief > Interface IP-Address OK? Method Status > Protocol > FastEthernet0/0 1.1.1.2 YES manual up > up > Serial0/0 3.3.3.2 YES manual up > up > FastEthernet0/1 2.2.2.2 YES manual up > up > Serial0/1 4.4.4.2 YES manual up > up > Loopback200 200.200.200.200 YES manual up > up > > R2#sh ip route 100.100.100.100 > Routing entry for 100.100.100.100/32 > Known via "ospf 1", distance 110, metric 11, type intra area > Last update from 2.2.2.1 on FastEthernet0/1, 00:03:50 ago > Routing Descriptor Blocks: > 2.2.2.1, from 0.0.1.0, 00:03:50 ago, via FastEthernet0/1 > Route metric is 11, traffic share count is 1 > * 1.1.1.1, from 0.0.1.0, 00:03:50 ago, via FastEthernet0/0 > Route metric is 11, traffic share count is 1 > R2#conf t > Enter configuration commands, one per line. End with CNTL/Z. > R2(config)#int s0/1 > R2(config-if)#ip os > R2(config-if)#ip ospf co > R2(config-if)#ip ospf cost 10 > R2(config-if)#int s0/0 > R2(config-if)#ip ospf cost 10 > R2(config-if)#do sh ip route 100.100.100.100 > Routing entry for 100.100.100.100/32 > Known via "ospf 1", distance 110, metric 11, type intra area > Last update from 4.4.4.1 on Serial0/1, 00:00:23 ago > Routing Descriptor Blocks: > 4.4.4.1, from 0.0.1.0, 00:00:23 ago, via Serial0/1 > Route metric is 11, traffic share count is 1 > 3.3.3.1, from 0.0.1.0, 00:00:23 ago, via Serial0/0 > Route metric is 11, traffic share count is 1 > 2.2.2.1, from 0.0.1.0, 00:04:40 ago, via FastEthernet0/1 > Route metric is 11, traffic share count is 1 > * 1.1.1.1, from 0.0.1.0, 00:04:40 ago, via FastEthernet0/0 > Route metric is 11, traffic share count is 1 > > and also a quick look at the CEF table for that route for per-packet vs. > per-destination: > > R2#sh ip cef 100.100.100.100 > 100.100.100.100/32, version 29, epoch 0, per-destination sharing > 0 packets, 0 bytes > via 4.4.4.1, Serial0/1, 0 dependencies > traffic share 1 > next hop 4.4.4.1, Serial0/1 > valid adjacency > via 3.3.3.1, Serial0/0, 0 dependencies > traffic share 1 > next hop 3.3.3.1, Serial0/0 > valid adjacency > via 2.2.2.1, FastEthernet0/1, 0 dependencies > traffic share 1 > next hop 2.2.2.1, FastEthernet0/1 > valid adjacency > via 1.1.1.1, FastEthernet0/0, 0 dependencies > traffic share 1 > next hop 1.1.1.1, FastEthernet0/0 > valid adjacency > 0 packets, 0 bytes switched through the prefix > tmstats: external 0 packets, 0 bytes > internal 0 packets, 0 bytes > R2(config-if)#int f0/0 > R2(config-if)#ip load-sharing per-packet > > R2(config-if)#do clear ip route * > > R2(config-if)#do sh ip cef 100.100.100.100 > 100.100.100.100/32, version 27, epoch 0, per-packet sharing > 0 packets, 0 bytes > via 4.4.4.1, Serial0/1, 0 dependencies > traffic share 1, current path > next hop 4.4.4.1, Serial0/1 > valid adjacency > via 3.3.3.1, Serial0/0, 0 dependencies > traffic share 1 > next hop 3.3.3.1, Serial0/0 > valid adjacency > via 2.2.2.1, FastEthernet0/1, 0 dependencies > traffic share 1 > next hop 2.2.2.1, FastEthernet0/1 > valid adjacency > via 1.1.1.1, FastEthernet0/0, 0 dependencies > traffic share 1 > next hop 1.1.1.1, FastEthernet0/0 > valid adjacency > 0 packets, 0 bytes switched through the prefix > tmstats: external 0 packets, 0 bytes > internal 0 packets, 0 bytes > > http://www.cisco.com/en/US/products/hw/modules/ps2033/prod_technical_reference09186a00800afeb7.html > > -- > Garry L. Baker > > "There is no 'patch' for stupidity." - www.sqlsecurity.com > > > On Sat, Jul 31, 2010 at 10:26 AM, Mohammed Aftab Memon < > aftabmemon12_at_gmail.com> wrote: > >> Hello All, >> >> There was some problem with my yahoo id and from days I was not getting >> any >> emails from this group. >> >> Please assist me on my below query. >> * >> Quote\\ >> *Hello Group, >> >> I have completed my preparation for OSPF but still feel that there is >> something missing. >> >> When I compared it with other protocols I realized that the Load balancing >> over OSPF is not done. >> >> I have been though video material of different vendors but stll I did not >> find in any of them. >> >> MIght be I am wrong or might be I did not concentrate if they did cover >> that >> topic during their lecture. >> >> I did find something related to load balancing which talks about Max - >> lsa. >> >> Can some one please advise me on this. >> >> >> Like if we have 2 routers with 3 redundant link between them, how wil the >> ospf load balance between them ? >> >> >> Also is there any specific command with which we can see only the flow of >> LSA's ? >> >> *Unquote* >> >> Regards >> Mohammed Aftab Memon >> >> --- On *Sun, 25/7/10, Aftab Memon <aftab.memon_at_ymail.com>* wrote: >> >> >> From: Aftab Memon <aftab.memon_at_ymail.com> >> Subject: Fw: OSPF - Load balancing >> To: "ccielab" <ccielab_at_groupstudy.com> >> Date: Sunday, 25 July, 2010, 6:37 AM >> >> FYI Group >> >> Regards, >> >> Mohd Aftab MEMON >> Network Analyst >> >> --- On *Sat, 24/7/10, Aftab Memon <aftab.memon_at_ymail.com>* wrote: >> >> >> From: Aftab Memon <aftab.memon_at_ymail.com> >> Subject: OSPF - Load balancing >> To: ccielab_at_groupstudy.com >> Date: Saturday, 24 July, 2010, 5:49 AM >> >> Hello Group, >> >> I have completed my preparation for OSPF but still feel that there is >> something missing. >> >> When I compared it with other protocols I realized that the Load balancing >> over OSPF is not done. >> >> I have been though video material of different vendors but stll I did not >> find in any of them. >> >> MIght be I am wrong or might be I did not concentrate if they did cover >> that >> topic during their lecture. >> >> I did find something related to load balancing which talks about Max - >> lsa. >> >> Can some one please advise me on this. >> >> >> Like if we have 2 routers with 3 redundant link between them, how wil the >> ospf load balance between them ? >> >> >> Also is there any specific command with which we can see only the flow of >> LSA's ? >> >> Regards, >> >> Mohd Aftab MEMON >> Network Analyst >> >> >> Blogs and organic groups at http://www.ccie.net >> >> _______________________________________________________________________ >> Subscription information may be found at: >> http://www.groupstudy.com/list/CCIELab.html Blogs and organic groups at http://www.ccie.netReceived on Sat Jul 31 2010 - 12:45:04 ART
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