3 Mb question

I've got what seems to me like an innocuous question for this list...

Someone is requesting access to about 3 mb of traffic up/dn. I figure 2
T1s will give them the 3 Mb I need, but I'm looking for suggestions on
either efficiently combining those 2 to get the most bandwidth for their
buck or else I have to look at getting them a ds3 and scaling back to
what they need.

Is there an good low end suggestion for making effective use of 2 T1s to
give 3 Mb of bandwidth? In practice, I've seen 2 T1s load balanced with
CEF not do very well at giving a full 3 Mb. (This was without turning on
per-packet CEF)

I'm not personally experienced with MLPPP or mux hardware if that helps,
but I could get it set up if that's the consensus as the best option.
The NRC of something that would effectively couple the 2 T1s would
easily beat the MRC of a DS3 which I think might be overkill for just 3

Thanks for suggestions and tips.


multilinking t1s will work fine.

but depending on your customer, there are lots of things between a T1 and DS3..
such as 10Mb ethernet


Hash: SHA1

...also look into IMA (inverse multiplex atm).


Gerald wrote:

Hi Gerald -

If you search the list for ip load-sharing per-packet you will see how
we manage all of our multi-customer T1s.

Never had any long term luck with MLPPP.

If you search the list for ip load-sharing per-packet you will see how
we manage all of our multi-customer T1s.

Never had any long term luck with MLPPP.

We have used both, and have found that MLPPP gives better results for
real-time applications like voice at the cost of increased CPU. For
generic data links, ip load-sharing per packet works fine. If the source
and destination traffic is reasonably diverse, simple equal cost routes
without per-packet will work as well, but you won't get greater than
1.5mbps for a given flow.

Hello All , Where can I find info about this range/ip & who
   has routing respnsibility for it ? I have searched -all-
   RIR's & all say they don't have any information on it at any
   levels . Tia , JimL

   APNIC reports this which is a little bit more info , But ...

inetnum: -
descr: Early registration addresses
remarks: ------------------------------------------------------
remarks: Important:
remarks: Networks in this range were allocated by InterNIC
remarks: prior to the formation of Regional Internet
remarks: Registries (RIRs): APNIC, ARIN, LACNIC and RIPE.
remarks: Address ranges from this historical space have now
remarks: been transferred to the appropriate RIR database.

san francisco unified school district ::

   Steve Huey
   San Francisco Unified School District
   135 Van Ness Avenue #300
   San Francisco, CA 94102
   (415) 241-6169

Hello Bill , Which tool or RIR did you dig that out of ?
     Tia , JimL

old IANA/SRI/Netsol data is occasionally useful

premature... :frowning:

  this block is chopped up into /24 bits... sfusd only has some of
  it. Waste Management (WM.COM) has some, as does FUnet (finland)
  and ATT.net. - which /24s are giving you fits?


What about MFR (Multilink Frame-Relay)? What hardware was your MLPPP bad
experience on? I have a 7206 I'll be using for my end of this. I've seen
some web pages that discuss some problems (perhaps resolved already)
in the 7500 series with MLPPP. I'm curios if anyone who has had a bad
experience with MLPPP could say what hardware they were using and if the
problem was determined what is the most frequent cause?

I guess I'm fishing for caveats from experience to MLPPP or MFR now.

Suggestions summarized went like this:

- If you can afford it hardware mux the lines, but they normally hand
off as v.35 or HSSI which means more hardware, more $$ etc. This is the
most stable of the bunch but the most expensive as well. (This is not
an option for us.)

- MLPPP and per-packet CEF are tied for second place. Both are
inexpensive ways to bond the lines. Both have their pros and cons. For
experience purposes I would try this MLPPP first before trying a CEF
option again. I'll try per-packet CEF on an internal dual-T1 setup when
I upgrade one of our routers on it. I don't want to try adding too much
to the antique 2500 I'm replacing.

- MFR or Multilink Frame-Relay was a distant 3rd. It seems to do all of
what I want, with less overhead than MLPPP. I'm not sure how tested this
option is or if it would require an IOS upgrade for me or the client.

- Putting ATM lines together with duct tape (AKA IMA) does not sound
appealing in any way. Research yourself if you are looking for a really
really low-tech 3 Mb connection, but the first time one of those ATM
lines flakes out I think you would be screwed. I'm not a fan of ATM for
B2B personally unless it's a backup.

Thanks for the input from all that replied. I learned a few new
technologies and some more stuff to read up on.


Hello Bill , Yes old data can be very handy :wink: .
   The /24 of interest s/b . Tia , JimL