Bonded T-1's and 2811

Unanswered Question
Jan 4th, 2010
User Badges:

Question is how much bandwidth should we see with a 2811 and an IMA bundle pack (AIM-IMA and 2 dual port VWIC-2MFT-T1.  We are utilizing 3 t-1's in this scenario, so one should expect a 4.5 by 4.5.  But I though I read that the 2811 could only handle up to @ 3.5 by 3.5, and that the 2821 was necessary to gain the max speed?  Is this true?

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Giuseppe Larosa Tue, 01/05/2010 - 02:21
User Badges:
  • Super Silver, 17500 points or more
  • Hall of Fame,

    Founding Member

Hello Ken,

if the ATM IMA can handle the three T1 you should be fine. However, ATM IMA has its own overheads so you cannot get 4.5 Mbps of user traffic.

the ATM IMA bundle with 4 E1 is declared supported on C2811 see table 8 in datasheet

so you should be fine

Hope to help


Ronit Bhattacharjee Tue, 01/05/2010 - 10:35
User Badges:
  • Bronze, 100 points or more

There is no theoretical limit (other than the number of ports which you can stuff in) but for 2811, more than 2 T1s would start affecting performance (when used along with other services like access control lists (ACLs), quality of service (QoS), and IP Security (IPSec).

However, for most practical uses, you shouldn't face any issues

Cisco 2800 Series Performance


Recommended Performance with Services Enabled (IMIX traffic)

Cisco 2801

Up to 1 T1/E1/xDSL

Cisco 2811

Up to 2 T1/E1s/xDSL

Cisco 2821

Up to 4 T1/E1s/xDSL

Cisco 2851

Up to 6 T1/E1s/xDSL

See this


This Discussion