07-03-2009 09:17 PM - edited 03-04-2019 05:19 AM
Hi all,
Iam having an NFC configured for monitoring the port traffic for Cisco GSR routers.It is showing very less output traffic and the input traffic is showing correctly.Iam exporting a version 5.Please assist me with your possibilities.
globally configured:
ip flow-sampling-mode packet-interval1000
ip flow-export source Loopback0
ip flow-export version 5
ip flow-export destination <ip add> 9996
ip tacacs source-interface Loopback0
ip flow-cache timeout active 1
ip flow-cache timeout inactive 15
In interface:
ip route-cache flow sampled output
Many thanks
Mahesh
07-03-2009 09:41 PM
Hello Mahesh,
you have sampling one packet every 1000 is processed by netflow on the router (choice for scalability implementation on GSR).
So the traffic volume is 1/1000 of the real traffic and short-lived flows like DNS queries are likely missed.
Then on the NFC you have faculty to introduce a multiplier.
It is important also to know what type of linecard you are using and the IOS version.
Be aware that netflow has started working on inbound only.
egress was added later.
according to
egress netflow accounting is supported in ios 12.2 SB
you are likely using a 12.0S version
Hope to help
Giuseppe
07-03-2009 10:00 PM
Hi,
Thanks for the response.
Iam using an ios version of 12.0(32)SY1 in my GSR.
from your response i came to know like with this IOS NFC could not detect the egress traffic.
So which is the proper IOS version need to use ,so that i can map the egress traffic in the NFC.
Many thanks
Mahesh
07-04-2009 08:39 AM
Hello Mahesh,
the answer could be negative with any IOS: when we deal with GSR we need to look also at what type of linecard we use.
you can chesk this with
sh gsr
sh inventory
sh diag
the type of engine the linecard has is important here.
To be noted that you can use ingress netflow by enabling it on other interfaces: for many years ISP providers used only inbound netflow and they were able to see traffic in their network.
At the NFC level you can define filters based on SNMP port ifindex to divide traffic received on external interfaces from traffic received by internal interfaces and directed to internet.
I think that for normal uses you can find an equivalent ingress only configuration that does what you need.
Edit:
unless internal interfaces are MPLS interfaces and the GSR is acting as PE / Edge LSR in this case egress netflow is probably the right tool.
Hope to help
Giuseppe
Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: