Packet loss while ping between local routers

[khuuleo]

Hi all,

I have an issue about my local routers. And i don't know, why did it happen. My system as below.

I have packet lost while ping from Router A to Router B, but ping from Router A to Router C does not have packet lost.

I tried changing the router with another router, and changing port switch between Router B and Router C, change MTU .... but the results have not changed.

But i tried changing Router B with my computer, there was packet lost. 

This is my configure on port g0/0 of router A and f0/0 of router B. (The configure on SW is default)

C2901:
interface GigabitEthernet0/1
ip address 101.53.X.X 255.255.255.252 secondary
ip address 202.151.Y.Y 255.255.255.248
ip nat inside
ip virtual-reassembly in
standby 1 ip 202.151.Z.Z
standby 1 preempt
standby 1 track 1 decrement 10
duplex auto
speed auto
!

C1921
interface FastEthernet0/0
description PORT_WAN
ip address 101.53.X.X 255.255.255.252
ip nat outside
ip virtual-reassembly
ip tcp adjust-mss 1400
speed auto
full-duplex

So cause of this issus and how can i fix it?

Many thanks.

[nurbol555]

Hello! it seems you have on router C2901 one ip address for Router B and secondary address for Router C. Why you don't try configure your connect from Router A to router B and C with sub interface? and use for evry connect between router A and B, A and C separate configuration

[khuuleo]

Hi nurbol555,

I have 2 range IP Public, so i use 1 for connect from Router A to Router C and 4 other device. And use the remaining ip for Router A and Router B.

I think issue not on my IP because I has changed Router B with my laptop and hasn't packets lost.

Thanks,

[nurbol555]

It seems you trying connect from router B to address 202.151.Y.Y 255.255.255.248, maybe your HSRP on port conflicting when you connecting to this address, try delete HSRP on port (standby config)

[khuuleo]

I connect from Router B to address 101.53.X.X 255.255.255.252, and this address don't run HSRP. I also tryed changing IP 101.53.X.X with IP 192.168.100.1/24 but it still has packets lost.

[nurbol555]

Try delete HSRP on port, if it's not working can we see all configuration?

[Georg Pauwen]

Hello,

check for CPU utilization as well with the 'show proc cpu' command...

[SOHAN HEGDE]

Hi,

Have  you try to change duplex settings on router B, it seems it is configured to FULL, can you change duplex to auto.

[khuuleo]

Hi SOHAN HEGDE,

at first, duplex setings on router B is default, So i tryed changing duplex FULL, but result hasn't changed.

Thanks.

[Georg Pauwen]

Hello,

in addition to the other posts, what is the uptime of the SG300 ? Have you tried to reboot it ? In the port settings of the SG300 (Port Management --> Port Settings), you can enable autonegotiation of flow control, you might want to give that a try.

Also, the default MTU and MSS settings should be sufficient, so remove the 'ip tcp adjust-mss 1400' from the FastEthernet interface.

[khuuleo]

Hi Georg Pauwen,

The uptime of the SG300 many days. I can't reboot it, because in behind switch SG300 is my system, and it can't disconnect.

Also, the function auto negotiation is enable on all port. 

I have tested 2 cases, MTU and MSS are default, and changed different parameter (as above is 1400). Packetloss at both cases above.

Thanks.