09-28-2009 07:39 AM - edited 03-04-2019 06:11 AM
I have 2 links between my data center and my DR site. They are both 150mbs lines. When I lose one of my links (VLAN264), which is the primary path, the other path (VLAN254) never becomes the preferred path. I can't the MSFC's on the DR 6509's to route data over that link.
My colleague thinks we have an issue with the metrics but I think since the delay and bandwidth are the same for both links we shouldn't have to manually tune the metrics EIGRP should handle that and we have a larger issue in the way routing is being handled.
Anyone have any ideas?
09-28-2009 07:49 AM
Roland
If the metrics are the same then you should be using both links at the same time anyway.
Regardless of that -
1) are the etherchannels at the main site and the DR site L2 etherchannels.
2) When you do a "sh ip route" on one of the DR 6500s do you see 2 equal cost paths to the main site or 1.
3) If the link between the DR site and main site fails on vlan 264 then do you not see any routes via vlan 254 ?
There are a lot of things that are unclear but the key one at the moment is why do the DR switches not have 2 equal cost paths in their routing tables.
Jon
09-28-2009 08:25 AM
Jon
1) Yes they are all L2 Etherchannels
2) No I only get 1 route.
3) I don't believe so I get any routes via VLAN254 when the VLAN264 route fails.
Roland
09-28-2009 08:48 AM
Roland
Okay then we need to work out why you are not getting both routes.
On DR02 can you post the output of
1) "sh ip eigrp neighbor"
2) pick a subnet that is in the primary building
"sh ip route
3) "sh ip eigrp topology
Even if the DR site preferred one path then once that path has been lost it should query for the other path.
It may well be you need to use IP SLA to keep track of which path is active as a L3 SVI will probably not go down even if the link does.
One other question about the etherchannels - are they trunk links ?
Jon
09-28-2009 09:07 AM
10
DR02#sho ip eig nei
IP-EIGRP neighbors for process 1173
H Address Interface Hold Uptime SRTT RTO Q Seq Type
(sec) (ms) Cnt Num
11 10.90.254.62 Vl264 14 1d14h 36 216 0 17198
2 10.90.24.130 Vl24 14 6w5d 7 200 0 132169
9 10.90.212.2 Vl212 12 44w4d 5 200 0 132159
10 10.90.210.2 Vl210 11 44w4d 7 200 0 132165
8 10.90.216.2 Vl216 14 44w4d 8 200 0 132163
7 10.90.218.2 Vl218 13 44w4d 7 200 0 132166
6 10.90.223.2 Vl223 10 44w4d 6 200 0 132167
5 10.90.214.2 Vl214 14 44w4d 7 200 0 132170
4 10.90.219.2 Vl219 14 44w4d 8 200 0 132162
3 10.90.208.2 Vl208 12 1y1w 6 200 0 132158
1 10.90.222.1 Vl222 14 2y20w 6 200 0 132164
0 10.90.221.2 Vl221 14 2y20w 6 200 0 132168
2)DR02#sho ip rou 10.90.88.0
Routing entry for 10.90.88.0/24
Known via "eigrp 1173", distance 90, metric 3072, type internal
Redistributing via eigrp 1173
Last update from 10.90.254.62 on Vlan264, 1d12h ago
Routing Descriptor Blocks:
* 10.90.254.62, from 10.90.254.62, 1d12h ago, via Vlan264
Route metric is 3072, traffic share count is 1
Total delay is 20 microseconds, minimum bandwidth is 1000000 Kbit
Reliability 255/255, minimum MTU 1500 bytes
Loading 1/255, Hops 1
3)DR02#sho ip eigrp top 10.90.88.0 255.255.255.0
IP-EIGRP topology entry for 10.90.88.0/24
State is Passive, Query origin flag is 1, 1 Successor(s), FD is 3072
Routing Descriptor Blocks:
10.90.254.62 (Vlan264), from 10.90.254.62, Send flag is 0x0
Composite metric is (3072/2816), Route is Internal
Vector metric:
Minimum bandwidth is 1000000 Kbit
Total delay is 20 microseconds
Reliability is 255/255
Load is 1/255
Minimum MTU is 1500
Hop count is 1
10.90.223.2 (Vlan223), from 10.90.223.2, Send flag is 0x0
Composite metric is (3328/3072), Route is Internal
Vector metric:
Minimum bandwidth is 1000000 Kbit
Total delay is 30 microseconds
Reliability is 255/255
Load is 1/255
Minimum MTU is 1500
Hop count is 2
10.90.218.2 (Vlan218), from 10.90.218.2, Send flag is 0x0
Composite metric is (3328/3072), Route is Internal
Vector metric:
Minimum bandwidth is 1000000 Kbit
Total delay is 30 microseconds
Reliability is 255/255
Load is 1/255
Minimum MTU is 1500
Hop count is 2
10.90.210.2 (Vlan210), from 10.90.210.2, Send flag is 0x0
Composite metric is (3328/3072), Route is Internal
Vector metric:
Minimum bandwidth is 1000000 Kbit
Total delay is 30 microseconds
Reliability is 255/255
Load is 1/255
Minimum MTU is 1500
Hop count is 2
Yes the Etherchannels are trunks.
I didn't consider that with the L3 SVI's. I thought that EIGRP would simply reconverge and use the remaining route.
09-28-2009 10:14 AM
Roland
You have no EIGRP neigborship running over lan 254 hence the reason that you are not seeing routes via the secondary link. It also accounts for the reason why when the primary link fails the secondary link it not used and DC02 never even queries down that link.
Can you post
1) "sh ip int br" from DR02 and CS02
2) "sh int gi3/48" from CS02
3) "sh int gi3/5" from DR02
note i'm assuming both the above are gig ports - you will need to adjust if they are not.
4) Also from both CS02 and DR02 can you post the "router eigrp .." config.
Jon
09-28-2009 12:40 PM
1) CS02# sho ip int brie
Interface IP-Address OK? Method Status Protocol
Vlan1 10.90.5.62 YES NVRAM up up
Vlan20 10.90.20.2 YES NVRAM up up
Vlan27 10.90.27.2 YES NVRAM up up
Vlan28 10.90.28.2 YES NVRAM up up
Vlan30 10.90.30.2 YES NVRAM up up
Vlan32 10.90.32.252 YES NVRAM up up
Vlan33 10.90.33.252 YES NVRAM up up
Vlan34 10.90.34.252 YES NVRAM up up
Vlan35 10.90.35.252 YES NVRAM up up
Vlan36 10.90.36.252 YES NVRAM up up
Vlan37 10.90.37.252 YES NVRAM up up
Vlan38 10.90.38.252 YES NVRAM up up
Vlan39 10.90.39.252 YES NVRAM up up
Vlan40 10.90.40.252 YES NVRAM up up
Vlan41 10.90.41.252 YES NVRAM up up
Vlan42 10.90.42.252 YES NVRAM up up
Vlan43 10.90.43.252 YES NVRAM up up
Vlan44 10.90.44.252 YES NVRAM up up
Vlan45 10.90.45.252 YES NVRAM up up
Vlan46 10.90.46.252 YES NVRAM up up
Vlan47 10.90.47.252 YES NVRAM up up
Vlan48 10.90.48.252 YES NVRAM up up
DR02#sho ip int brie
Interface IP-Address OK? Method Status Protocol
Vlan24 10.90.24.131 YES manual up up
Vlan208 10.90.208.3 YES NVRAM up up
Vlan210 10.90.210.3 YES NVRAM up up
Vlan212 10.90.212.3 YES NVRAM up up
Vlan214 10.90.214.3 YES NVRAM up up
Vlan216 10.90.216.3 YES NVRAM up up
Vlan218 10.90.218.3 YES NVRAM up up
Vlan219 10.90.219.3 YES NVRAM up up
Vlan221 10.90.221.3 YES NVRAM up up
Vlan222 10.90.222.2 YES NVRAM up up
Vlan223 10.90.223.3 YES NVRAM up up
Vlan264 10.90.254.61 YES manual up up
2)
CS02#sho int g3/48
GigabitEthernet3/48 is up, line protocol is up (connected)
Hardware is C6k 1000Mb 802.3, address is 0024.9798.7fdb (bia 0024.9798.7fdb)
Description:
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 1000Mb/s, media type is SX
input flow-control is off, output flow-control is off
Clock mode is auto
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:45, output 00:00:45, output hang never
Last clearing of "show interface" counters never
Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 699000 bits/sec, 623 packets/sec
5 minute output rate 6313000 bits/sec, 974 packets/sec
170455961 packets input, 25177255152 bytes, 0 no buffer
Received 7565405 broadcasts (3383536 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 0 multicast, 0 pause input
09-28-2009 12:42 PM
DR02> (enable) sho po 3/5
Port Name Status Vlan Duplex Speed Type
----- -------------------- ---------- ---------- ------ ----- ------------
3/5 connected trunk full 1000 1000BaseSX
Port Security Violation Shutdown-Time Age-Time Max-Addr Trap IfIndex
----- -------- --------- ------------- -------- -------- -------- -------
3/5 disabled shutdown 0 0 1 disabled 168
Port Num-Addr Secure-Src-Addr Age-Left Last-Src-Addr Shutdown/Time-Left
----- -------- ----------------- -------- ----------------- ------------------
3/5 0 - - - - -
Port Broadcast-Limit Multicast Unicast Total-Drop
-------- --------------- --------- ------- --------------------
3/5 - - - 0
Port Send FlowControl Receive FlowControl RxPause TxPause
admin oper admin oper
----- -------- -------- --------- --------- ---------- ----------
3/5 desired off off off 0 0
4)
DR02 router eigrp
router eigrp 1173
network 10.0.0.0
no auto-summary
no eigrp log-neighbor-changes
!
ip classless
no ip forward-protocol udp netbios-dgm
ip route 64.46.197.0 255.255.255.0 10.90.6.200
no ip http server
CD02 eigrp
router eigrp 1173
network 10.90.251.0 0.0.0.255
network 10.0.0.0
eigrp router-id 10.90.251.254
no eigrp log-neighbor-changes
no auto-summary
redistribute static
nsf
!
ip classless
09-28-2009 12:47 PM
Roland
There is no vlan 254 interface on either CS02 or DR02. Is this is a typo.
The ports that connect CS02 to DR02 ie. 3/48 on CS02 and 3/5 on DR02 - are they in vlan 254 ?. If they are and you don't have a L3 SVI for vlan 254 on both switches then they will not form an EIGRP neighborship across that backup link.
Jon
09-28-2009 10:14 AM
Jon
1) Yes they are all L2 Etherchannels
2) No I only get 1 route.
3) I don't believe so I get any routes via VLAN254 when the VLAN264 route fails.
Roland
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