cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
1033
Views
5
Helpful
21
Replies

Problem with T1 bridge w/2 1720 routers performance slow

xtremenet
Level 1
Level 1

I have a partial bridged T1 using 2 Cisco 1720 routers and the speed is very slow from lan to lan.

Here is the config:

Using 646 out of 29688 bytes

!

version 12.2

service timestamps debug uptime

service timestamps log uptime

no service password-encryption

!

hostname GW-MAC

!

logging queue-limit 100

enable secret 5 xxxxxxxxx

enable password xxxxxxx

!

memory-size iomem 25

ip subnet-zero

no ip routing

!

!

!

!

interface FastEthernet0

no ip address

no ip route-cache

no ip route-cache

full-duplex

bridge-group 1

!

interface Serial0

ip address 192.168.20.201 255.255.255.0

encapsulation ppp

no ip route-cache

bridge-group 1

!

ip classless

no ip http server

!

bridge 1 protocol ieee

!

line con 0

line aux 0

line vty 0 4

password xxxxxx

login

!

no scheduler allocate

Same config both sides with different host name and IP.

21 Replies 21

what out for Windows name resolutions, which sometimes can go as broadcasts.

As regards to performance of this router - even though everything on this router is implemented in software, yet with CEF performance is higher and can be upto 4Mbps, yet without CEF it's only 700Kbps. Software bridging is of the same performance as software switching - 700Kbps.

Vern

How are you managing to restrict traffic through the bridge to RDP and some Internet? Normally all broadcast, all multicast, and all unicast for destinations on the other side of the bridge are carried by the bridge (which is one reason that we generally recommend not to bridge LAN over T1).

There certainly might be a clocking issue or a noisy line issue and if so it could explain the poor performance. It might give us some insight into the issue if you would post the output of show service-module

HTH

Rick

HTH

Rick

Rick

I am not running WINS. I have some broadcasts but very little. That is why you saw very little traffic on the sho int ser 0 on Sunday.

I have contacted the ISP to check the provisioning of the T1.

I am begining to think I should route instead of bridge. I would like to solve the serial interface issue first. The following is the sho service-module. I did notice the timeslots = 1, odd!

GW-NBG#sho service-module

Module type is T1/fractional

Hardware revision is 0.96, Software revision is 0.2,

Image checksum is 0x73D70058, Protocol revision is 0.1

Receiver has no alarms.

Framing is ESF, Line Code is B8ZS, Current clock source is line,

Fraction has 1 timeslots (64 Kbits/sec each), Net bandwidth is 64 Kbits/sec.

Last module self-test (done at startup): Passed

Last clearing of alarm counters 2d17h

loss of signal : 0,

loss of frame : 0,

AIS alarm : 0,

Remote alarm : 1, last occurred 2d17h

Module access errors : 0,

Total Data (last 96 15 minute intervals):

0 Line Code Violations, 0 Path Code Violations

0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins

0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

Data in current interval (108 seconds elapsed):

0 Line Code Violations, 0 Path Code Violations

0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins

0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

GW-NBG#

Vern

The line about Fraction has 1 timeslots (64 Kbits/sec each), Net bandwidth is 64 Kbits/sec is certainly something to check out. If true it would certainly explain the poor performance.

HTH

Rick

HTH

Rick

Rick

In my config I have the service-module T1 timeslots = 20 on both routers. If the timeslots were misconfigured I thought I would not bring up the circuit.

Any idea how this is possible?

Vern

I am not sure how it would happen. I am not sure whether there is any other parameter that might be needed.

I do not have much experience with this issue but I see that there is a debug service-module command. I wonder if you turned on that debug, configured the service module to remove the timeslots and then configured the service-module again with the timeslots, if the debug would tell us anything useful?

HTH

Rick

HTH

Rick

Rick,

I have been working with the ISP and they will check the provisioning. I am at the point that I will erase the flash on each router and rebuild. I have another 1720 being shipped in tomorrow (just in case).

I will keep you posted. Than you for all your help!

Review Cisco Networking products for a $25 gift card