Urgent help in E1 Link bundling

[binoyjosephstanly]

Hi all

i want to connect 4 e1 links to my branch office, i want to achieve 8 mbps link, i want to bundle these 4 e1 lines to work like single e1 line.is it possible? what are the cards required for this?

kindly suggest

Regds

Binoy

[tekha]

Sounds like your are thinking on ppp multilink, here is an example:

http://www.cisco.com/en/US/tech/tk713/tk507/technologies_configuration_example09186a0080093c1d.shtml

It seems pretty easy, just write "ppp multilink" and "multilink-group 1" on each of the 4 psysical interfaces, and make a logical interface called "interface Multilink1".

[binoyjosephstanly]

thanks tekha,

but my E1 pri lines are like leased line's rt now i'm using it as a normal leased line, no need to dial in.so in this case what's the solution.

Regds

Binoy.

[tekha]

Sorry, but that was the first example I found regarding ppp multilink.

Here is another, that is closer to you problem.

http://www.cisco.com/en/US/tech/tk713/tk628/technologies_configuration_example09186a00800a5efa.shtml

[johansens]

If you're not running any PPP there now (encapsulation ppp) and you don't want to setup a multilink PPP link, you could always let CEF do the job..

All IOS routers do load-balancing by default if you have installed equal-cost routes in the routing-table. The problem would only be how the links are used. Standard setup for CEF is to use per-destination load-balancing.. which means a single session will only go through one link, leaving the other links 'dead'.. You can modify this behaviour with enabling per-packet load-balancing (you should absolutely run CEF for this, without CEF it would go in software=bad idea). Then each packet will be evaluated without concern to which flow the packet belongs. This can be hazardous with high-latency/low-bandwidth/high-variance links, but with your E1-links, this should pose no problem.

Check this page:

http://www.ciscotaccc.com/iprout/showcase?case=K20236117

And here for more on Load-balancing with CEF:

http://www.cisco.com/en/US/products/hw/modules/ps2033/prod_technical_reference09186a00800afeb7.html

[tekha]

I totally agree with you Johansen, that per-packet loadsharing using CEF would be the best way to go.

However binoyjosephstanly states that he wants the 4 lines to "work like single e1 line", that was why I recommended the multilink-thingy.

[Richard Burts]

I agree that given the original post which indicated that there was a requirement for all 4 linnks to operate as a single entity that multilink PPP is the only solution that really meets that requirement. And multilink PPP ia good with or without dialing.

A word of caution about using per packet load balancing (even with CEF). If you do per packet load balancing the load distribution over the links will be close but may not be really even (one link could happen to get a group of short packets while another link gets a group of large packets which would produce uneven usage of the links). Also when you specify per packet load balancing you open the door to issues with out of order delivery of packets. Depending on the aplication this could be really problematic (or not). With multilink the distribution over all the links will be even.

HTH

Rick

[binoyjosephstanly]

hi buddies

thanks to all for ur postings.

in my scenario i'm connecting from one branch to H.O

rt now 1 e1 link is there next week i will configure 3 more lines.

my H.O lan is 10.10.15.0/24 present wan ip is 10.15.21.0/30 ie. 10.15.21.4 at the H.O side router and 10.15.21.5 at the branch side.

rt now the routing entry at branch is

ip route 0.0.0.0 0.0.0.0 10.15.21.4

next week i will connect 3 more lines to H.O.

ip's will be

10.15.21.9 at branch and 10.15.21.10 at H.O for the 2nd link

10.15.21.13 at branch 10.15.21.14 at H.o 3rd link

10.15.21.17 at branch 10.15.21.18 at H.O 4th link.

so in this case how will i route.

at branch router if i route like this (look below.)

ip route 10.10.15.0 255.255.255.0 10.15.21.10

ip route 10.10.15.0 255.255.255.0 10.15.21.14

ip route 10.10.15.0 255.255.255.0 10.15.21.18

will this work?.all the 4 lines will work ? in this case how the traffic will be?.

regds

Binoy.

[amit-singh]

Hi,

As already pointed out by Rick and taking that into consideration i would suggest you to use MPPP and bundle all 4 E1 together.

The simplest configuration would be assigning an IP to the multi-link interface and using that as the next hop address to forward the packets. In this case even if one of the link goes down or comes back you dont need to change any thing. Please see the follwong configuration :

enable secret xxx

!

no network-clock-participate slot 1

no network-clock-participate wic 0

no aaa new-model

ip subnet-zero

ip cef

!

!

!

no ftp-server write-enable

!

!

!

!

interface Multilink1

ip address 192.192.0.2 255.255.255.0

ppp multilink

ppp multilink group 1

!

interface FastEthernet0/0

ip address 172.25.11.1 255.255.0.0

ip access-group 102 in

ip route-cache flow

duplex auto

speed auto

!

interface Serial0/0

no ip address

encapsulation ppp

no fair-queue

ppp multilink

ppp multilink group 1

!

interface Serial0/1

no ip address

encapsulation ppp

no fair-queue

ppp multilink

ppp multilink group 1

!

interface Serial0/2

no ip address

encapsulation ppp

no fair-queue

ppp multilink

ppp multilink group 1

!

!

ip classless

ip route 0.0.0.x.x.x.0 192.192.0.1

HTH,

-amit singh

[albert.remo]

Hi!

I agree that you use ppp multilink. Leased lines are very suitable for this because it doesn't care for the traffic passing through it. You can easily group them and yes point-to-point protocol is the easiest way to configure each interface. With the config that you provided, traffic will pass through these links based on the routing protocol (check your routing table) that you will be using. But most likely, traffic will pass through the first available link until the full bandwidth has been utilized then traffic will pass through the next link. Though this is also true with bundled E1s, bundling is advised as for the ease in configuration, and use of a single ip address rather than multiple addresses. Just make sure that all these E1s are provided by the same telco/provider so as to avoid some problems such as latency and interoperability issues.

Regards,

Albert

[Tony.henry]

Inverse multiplexing might be worth a look. Some telcos support this some don't. The IMA card might be worth a look into. But again I'm not sure you'll be able to simply place four E1's into one side and four into the other side and mux them together, without some intermediate ATM gear..

Tony

[nkumar2005]

kumar here

use "IP CEF" global command and in each interface

use the "IP load-sharing per-packet"

or go to cisco.com and search for "INVERMUX"

thanks