Can Cisco 2621XM handle 4 T1's using MLPPP?

I work in test on a product that supports MLPPP with 4 T1's.  I have configured a Cisco2621XM for MLPPPx4 using 2 VWIC dual-T1 controllers.  When performing an FTP download, the bandwidth drops to zero every few seconds, resulting in a choppy graph of bandwidth over time, which peaks at about 5Mbps, but average throughput is significantly less.

If I use two of my company's product back-to-back, the throughput graph is quite steady at around 5Mbps (would like to see more, but at least it's steady).  If I place two Cisco2621XM's back-to-back, I get pretty bad results, though different (whole T1 lines appear to drop out for long periods of time).  I'm beginning to believe I need to invest in a higher-performance router.  

During the data transfer on the Cisco2621XM, "show processes cpu" says about 30-40% cpu is being used, for what it's worth.

Here's my running config:

Router7008#show run
Building configuration...

Current configuration : 1752 bytes
!
version 12.3
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router7008
!
boot-start-marker
boot-end-marker
!
!
no network-clock-participate slot 1
no network-clock-participate wic 0
no aaa new-model
ip subnet-zero
ip cef
!
!
!
!
!
!
!
!
!
!
!
!
!
!
username ******** password 0 ********
!
!
controller T1 0/0
 framing esf
 fdl both
 clock source internal
 linecode b8zs
 cablelength short 133
 channel-group 0 timeslots 1-24 speed 64
!
controller T1 0/1
 framing esf
 fdl both
 clock source internal
 linecode b8zs
 cablelength short 133
 channel-group 0 timeslots 1-24 speed 64
!
controller T1 0/2
 framing esf
 fdl both
 clock source internal
 linecode b8zs
 cablelength short 133
 channel-group 0 timeslots 1-24 speed 64
!
controller T1 0/3
 framing esf
 fdl both
 clock source internal
 linecode b8zs
 cablelength short 133
 channel-group 0 timeslots 1-24 speed 64
!
!
!
interface Multilink1
 ip address 10.10.45.1 255.255.255.0
 ppp multilink
 ppp multilink group 1
!
interface FastEthernet0/0
 no ip address
 shutdown
 duplex auto
 speed auto
!
interface Serial0/0:0
 no ip address
 encapsulation ppp
 ppp multilink
 ppp multilink group 1
!
interface FastEthernet0/1
 ip address 10.10.20.103 255.255.255.0
 duplex auto
 speed auto
 no cdp enable
!
interface Serial0/1:0
 no ip address
 encapsulation ppp
 ppp multilink
 ppp multilink group 1
!
interface Serial0/2:0
 no ip address
 encapsulation ppp
 ppp multilink
 ppp multilink group 1
!
interface Serial0/3:0
 no ip address
 encapsulation ppp
 ppp multilink
 ppp multilink group 1
!
ip http server
ip classless
ip route 0.0.0.0 0.0.0.0 10.10.20.10
!
!
!
!
!
!
!
!
!
line con 0
line aux 0
line vty 0 4
 login
!
!
end
sniderman42Asked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

giltjrCommented:
What errors are you seeing on any of the Interfaces?  Including the fast Ethernet interfaces, a duplex mis-match on a 100 Mbps interface can cause poor throughput.
0
RPPreacherCommented:
We just implemented MLPPP in one office that did not have access to a T3 (using 4 T1s).  Our experience was serious performance degradation with less than a 2811.
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
sniderman42Author Commented:
not seeing any errors on interfaces.  have tried setting specific duplex & speed but no change.  Will try to get a 2811 or better to try.
0
sniderman42Author Commented:
Was not able to find a 2811 to try.  Did get some feedback from Cisco that 2821 would be the minimum they would recommend.  They felt that 2811 should only be used for two T1's, but of course the manufacturer will always leave headroom in recommendations.
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Routers

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.