Router inside interface not ping to directly connected device and router became slow..

[Tarjeet Singh]

Client informed me that router line is down. Router R1 g0/0 outside and Gig0/1 inside. booth public ip..

I tried to ping WAN outside and Inside interface of R1. I could see heavy packet loss on WAN interface of R1. It was not completely down. I requested Data center tech to unplug cable from inside interface of R1. Tech unplugged cable and traffic moved to R2 and all websites came back up via backup line R2.

I found that when tech unplugged inside lan cable from router R1 then straight away R1 WAN interface become reachable again. I guess that there was issue with router hardware or software.

Please advise what could be issue here. last time. Just inside interface was dropping packets which is connected directly to Switch 2960. I couldnt ping to swtich loopback.

This time impaceted WAN as well. When WAn became reachable then i tried to telnet on to router and it was very slow. I unplugged Inside LAN cable physically then WAN became reachable again.  3845 router Full BGP routing table and inside OSPF with defult route to ASA with lower metric..

[David Salazar]

When disconnecting the network router, the router responds faster?

You could do the following procedure to collect information that will be useful:

- Connect to the router via console

- Disconnect all network ports (serial, Ethernet, etc) you have connected

- Check the router's processing at the time (a sample of such information to allow you to compare) -> show process cpu sorted 5sec

- Raise the Router's WAN connection and has several shots of the command -> show process cpu sorted 5sec

- Raise the Router's LAN connection and has several shots of the command -> show process cpu sorted 5sec

At the time you perceive that the router becomes slow, returns the last change, ie the interface disconnects again. And you got to show me the command -> show process cpu sorted 5sec

[Tarjeet Singh]

Hi David thanks for response,

  I checked sh proc cpu history and i didnt see any high spike in last 60min. it should show me high utilization cus issue was there from last 25min when i consoled in router. BGP has full routing table and inside has OSPF default routes.

IOS was 09 and i have upgraded to IOS 12.

Interesting thing is last week when this issue occurred first time. Only inside interface went down. I couldn’t ping to directly connected switch 2960 on inside interface. While I could ping to inside interface from outside over wan BGP and inside interface was pinging itself as well. I restarted router that time and still same issue then reseted cable and swtich then it gone.

but this time router was slow. and WAN was impacted.

[David Salazar]

Routers that model is? could you share a show version?

I recommended using the command: show process cpu | show process cpu sorted 1min | show process cpu sorted 5 sec

The show process cpu history command is not very useful in this case, because what we want to identify whether there is a process that affects the CPU.

How much RAM and Flash is the device? What were the memory requirements for the version of IOS you updated?

Actulizaste why the IOS? IOS is always slow? Or at specific times?

The following link can help you think, the work to be done is thorough:

http://packetlife.net/wiki/troubleshooting-commands-ios-devices/

[Tarjeet Singh]

Router is 3845. but when this issue happened last week, router was not slow. it was OK and WAN was reachable. Only inside interface connected directly to 2060 was not able to ping anything. it was pinging once a while.

But yesterday. Wan and inside interface had problem. but shut down the inside and wan was reachable but router was slow.. yea i checked CPU 60min proccess. and it was not showing any spike.

Router11 uptime is 2 hours, 20 minutes

System returned to ROM by power-on

System restarted at 11:48:22 PDT Thu Mar 14 2013

System image file is "flash:/c3845-advipservicesk9-mz.124-15.T17.bin"

Cisco 3845 (revision 1.0) with 484351K/39936K bytes of memory.

Processor board ID FTX1144A3NF

2 Gigabit Ethernet interfaces

1 Virtual Private Network (VPN) Module

DRAM configuration is 64 bits wide with parity enabled.

479K bytes of NVRAM.

62720K bytes of ATA System CompactFlash (Read/Write)

Configuration register is 0x2102

new IOS need DRAM 256/64 flash. so it is fine.. IOS was slow yesterday and last week it was not slow when issue happened.

[David Salazar]

I really like to help, but it is critical to see the output of the command:

show process cpu sorted 5sec

When a router is slow can be for many reasons, but must be sought that could be causing process disruptions CPU out of the ordinary and be able to isolate the fault.

Please review this link:

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/troubleshooting/cpu_util.html

Troubleshooting Router Hangs

http://www.cisco.com/en/US/products/hw/routers/ps359/products_tech_note09186a0080106fd7.shtml

Memory Problems

http://www.cisco.com/en/US/products/sw/iosswrel/ps1831/products_tech_note09186a00800a6f3a.shtml

Troubleshooting High CPU Utilization Due to Interrupts

http://www.cisco.com/en/US/products/hw/routers/ps359/products_tech_note09186a00801c2af0.shtml

Are a excelent tool, a core dump file:

http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/products_tech_note09186a00800c7d59.shtml