cisco 2921 - Router

[SC856]

llo, 

I am looking for assistance with an issue that is causing downtime to site, any help would be much appreciated!

We had a previous configuration for a layer 2 10 mbps circuit between sites which worked

A END London 3850 switch 

B END London 2921 router

Previous workig Configuration for the 10mbps circuit 

A END - 

interface GigabitEthernet1/0/10

description WAN (Remote Branch) R1.CF Gi0/0 Chesterfield Virgin 10Mb/s #CAL0065214 (via X-Connect Acc14 Gi3/39)

switchport trunk allowed vlan 410,411,414

switchport mode trunk

bandwidth 10000

no cdp enable

B END - 

interface GigabitEthernet0/0

description WAN BCR1.GR Gi2/18 | Goswell Rd DC VMB 10Mb/s ID:CAL0065214

mtu 9000

no ip address

duplex full

speed 10

rj45-auto-detect-polarity disable   

 no cdp enable

service-policy output PM-QOS-WAN

We have ordered an upgraded 100mbps circuit and cutover to this new circuit last week using same config on interfaces at both ends,  but we have been advised to set full duplex and speed 100 at both ends of link, which has been done.  Our equipment at both ends shows up and up between us and the provider equipment.  We cannot however pass traffic between both ends since cutover.  The provider had a couple of issues, but now tell us an end to end test has passed.

Our new port config is thus:-

 A End

!

interface GigabitEthernet1/0/11

description ***NEW COGENT CIRCUIT via VM  *** CHESTERFIELD 100Mb/s (VM Ref:CAL0353583)

switchport trunk allowed vlan 410,411,414

switchport mode trunk

bandwidth 100000

speed 100

duplex full

no cdp enable

B END

interface GigabitEthernet0/0

description WAN BCR1.GR Gi2/18 | Goswell Road London

mtu 9000

no ip address

duplex full

speed 100

no cdp enable

service-policy output PM-QOS-WAN

end

I can see that there is a rj45-auto-detect-polarity disable, which I cannot reapply to the B end 2921 router.  Would this have any bearing on the issue. 

Any help in understanding why this new 100 mbps circuit will not come up is gratefully received.

Thankyou

Stephanie 

[paul driver]

Hello

---

@SC856 wrote:

A END London 3850 switch 

Previous workig Configuration for the 10mbps circuit 

A END - 

interface GigabitEthernet1/0/10

description WAN (Remote Branch) R1.CF Gi0/0 Chesterfield Virgin 10Mb/s #CAL0065214 (via X-Connect Acc14 Gi3/39)

switchport trunk allowed vlan 410,411,414

switchport mode trunk

bandwidth 10000

no cdp enable

A End

!

interface GigabitEthernet1/0/11

description ***NEW COGENT CIRCUIT via VM  *** CHESTERFIELD 100Mb/s (VM Ref:CAL0353583)

switchport trunk allowed vlan 410,411,414

switchport mode trunk

bandwidth 100000

speed 100

duplex full

no cdp enable

---

First of all, it looks like your using a different physical port at site A, why is that?
Have you tired not hardcoding the interfaces and leaving them to auto-negotiate.

Also, at site B have your tried using a crossover cable? The reason being site B had this rj45-auto-detect-polarity disable which personally i have never come across, But a quick CCO search suggests it used like MDIX for cabling between router and switch and as that interface doesn’t support it now, maybe you require a crossover cable?

Lastly try and perform a TDR test on the switches interface and see what results it comes back with?

Site A
test cable tdr interface gig1/0/11

[SC856]

Thanks for your reply.
I ran the cable Tdr test - not completed suggests test failed?
Interface Speed Local pair Pair length Remote pair Pair status
--------- ----- ---------- ------------------ ----------- --------------------
Gi1/0/11 100M Pair A N/A N/A Not Completed
Pair B N/A N/A Not Completed
Pair C N/A N/A Not Completed
Pair D N/A N/A Not Completed
The A end different port was used, to leave the 10mbps port as was in case we needed to cut back and run the new service from port gi1/0/11. The issue is that with the old 10mbps port, the provider cancelled the line 3 weeks fter we had given them 3 months notice to terminate!!! I could revert to the old 10mbps as now reinstated apparently, but it's a legacy line and I have been told it will not work after March 31st anyway, so may as well pursue the cutover to the new circuit, rather than have to go through this pain again at end of March.
Configs of Gi1/0/11 and old 10 mbps port below:--
interface GigabitEthernet1/0/11
description ***NEW COGENT CIRCUIT via VM *** 100Mb/s (VM Ref:CAL0353583)
switchport trunk allowed vlan 410,411,414
switchport mode trunk
bandwidth 100000
speed 100
duplex full
no cdp enable
end

SW01-EDGE.GR#sh run int gi1/0/10
Building configuration...

Current configuration : 250 bytes
!
interface GigabitEthernet1/0/10
description WAN (Remote Branch) R1.CF Gi0/0 10Mb/s #CAL0065214 (via X-Connect Acc14 Gi3/39)
switchport trunk allowed vlan 410,411,414
switchport mode trunk
bandwidth 10000
no cdp enable
end

[Richard Burts]

Looking at a post earlier in this discussion it shows interfaces on both ends as up/up. And each end show some number of packets input and output

120547 packets input, 20789847 bytes, 0 no buffer

578802 packets output, 51823608 bytes, 0 underruns

I wonder if this is traffic being carried on vlan 1. Which makes me wonder what would be the result if you configure on 3850 interface vlan 1 and configure an IP address on it. And if on the router you configure an IP address (in the same subnet) on the physical interface? Would they be able to communicate over vlan 1?

[SC856]

Apologies for delay in replying to this post.  After much back and forth, the issue turned out to be our provider duplex/speed setting mismatch.  Unfortunately, their service desk didnt spot the issue on the port, stating all was ok for a few day. Eventually, I tracked down the 3rd party switch  installation engineer who found the problem within 5 mins!.

Thanks for your help

[Richard Burts]

Thanks for the update. Glad to know that you found the issue and that it turned out to be a mismatch of settings between you and the provider. A well deserved +5 for sharing this information.

[SC856]

Apologies for delay in replying to this post.  After much back and forth, the issue turned out to be our provider duplex/speed setting mismatch.  Unfortunately, their service desk didnt spot the issue on the port, stating all was ok, so I tracked down the installation engineer who found the problem within 5 mins!.

Thanks for your help