01-26-2010 03:15 AM - edited 03-04-2019 07:18 AM
We are using redundant Pont to Point STM / DS3 over the wan for connecting with other remote locations, Load sharing and redundancy is happening perfectly with OSPF, but if media Fluctatues then packet srart drops and connectivity goes down. Please tell how to resolve this issue.
Regards,
Prince
MTS India
01-26-2010 07:40 AM
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01-27-2010 02:30 AM
Hi Prince
I am afraid if you can do something for this, since the problem is with the physical link you tend to see packet drops when you are doing load sharing with multiple physical links. Better way to overcome is to do proper testing of both the physical links before accepting the same from your telco.
Normally you do a 48Hrs error testing before you accept the link and pass on the live traffic onto it.
regds
01-27-2010 04:06 AM
Hi Kumar
Thanks for your reply...
Can I use "IP SLA" or any other machnisim, which count errors on particular link and if errors crossed a certain limit then traffic should shift on Other stable link without disconnection in SCTP packets.
Regards,
Prince
01-27-2010 05:12 AM
Hello Prince,
if all devices are C7600 you can think to use BFD to perform IP fast convergence:
if the issue is errors from time to time it can help to skip using the affected link
see
http://www.cisco.com/en/US/docs/ios/iproute_bfd/configuration/guide/irb_bfd.html
feature navigator says:
C7600 sup720/MSFC3
you can use an IOS 12.2(33) SRD3 or SRE
search by feature type BFD OSPF Support for BFD over IPv4
Hope to help
Giuseppe
01-31-2010 07:17 AM
Hello Giuslar,
Thanks for your valuable inputs.
I have gone through below the mentioned link on BFD, Please clarify my few queries on the same.
As I mentioned earlier, we are carrying SCTP (Signaling) traffic on P2P links DS3 & -Multilinks (Channelized Optical E1's) on the WAN with OSPF. During the Fluctuation, we got input and output errors on link. Find below the link detail. but link does'nt go down, OSPF failover mechnism works only when the active link goes down.
Is BFD can help to shift the traffic from fluctuated link to another suitable link?
WAN-RTR-CHN-7606-001#sh int Serial2/0/0.1/2
Serial2/0/0.1/2 is up, line protocol is up
Hardware is SPA-1XCHSTM1/OC3
Description: ***Railtel_DS3_CHN_BANGA_PDSN***
Internet address is 10.131.0.81/30
MTU 4470 bytes, BW 44210 Kbit, DLY 200 usec,
reliability 255/255, txload 101/255, rxload 37/255
Encapsulation PPP, LCP Open, multilink Closed
Open: IPCP, CDPCP, crc 16, loopback not set
Keepalive set (10 sec)
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters 2w5d
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 4627
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 6467000 bits/sec, 2616 packets/sec
5 minute output rate 17553000 bits/sec, 4407 packets/sec
2650934928 packets input, 618880707937 bytes, 0 no buffer
Received 0 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
0 parity
159357 input errors, 21527 CRC, 31479 frame, 0 overrun, 0 ignored, 106351 abort
3626753481 packets output, 2327272737770 bytes, 0 underruns
7892 output errors, 0 applique, 11 interface resets
0 output buffer failures, 0 output buffers swapped out
11 carrier transitions no alarm present
DSU mode cisco, bandwidth 44210 Kbit, scramble 0, VC 21, non-inverted data
01-31-2010 07:36 AM
Hi,
Are ypou trying to supress exessive flaps on the physical interface which causes routing protocol instability, If So, then I would suggest you look at (IP Event dampening) feature.
have a look at this link for more info:
http://www.ciscosystems.ch/en/US/docs/ios/12_0s/feature/guide/s_ipevdp.html
HTH
Mohamed
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