Combine/Merge bandwidth of 2 ISP and get single

[Kuldeep singh]

Hi Experts,

                  I have cisco 1841 router and  two types of ISP line (Different provider):

                 1. Lease line = 2 mbps   ( it is terminated over cisco 1841 router);   For internet-access purpose

                 2. DSL = 1 mbps;    For internet-access purpose

                 Our cisco 1841 router have only two fastethernet port, first for WAN Port where 2 mbps lease line terminated ,

                 second for LAN which is connected to Cisco switch and  1 mbps adsl line running seperatly which  is not

                 part of cisco 1841 router. i am planning to buy HWIC card for extra wan port on existing router where

                 i will terminate 1 mbps adsl  line or may be other provider lease line.

                 I want to merge or aggregate both WAN link, My concern is to merge both line (2+1) and

                 get single one (Just like as Etherchannel thing) , get 3mbps for LAN for internet access.

                 Plz explain with configuration. 

                 is it possible ???

                 if it is not possible through this scenerio then plz suggest me alternate methods or any Dedicated hardware for this ??

                Note That:

                A. we have only single location

                B. we are not using any routing protocols and do not want use Routing protocols.

KS

[Giuseppe Larosa]

Hello Kuldeep,

the link provided by Paolo should work I have tested it in another broswer

http://www.cisco.com/en/US/tech/tk648/tk361/technologies_configuration_example09186a0080950834.shtml

as Paolo and Rick have explained you cannot combine the two internet access link speeds, you can perform load sharing in internet access using the link that Paolo has provided.

With this configuration some internal hosts will be served by link#1 and other ones by link#2 depending on CEF hashing.

We can say that both links will be used to access the internet this is what you achieve.

Basically you need two default static routes and two route-map based NAT rules , the route-map allow to check the outgoing interface that will be used before NAT translation and allows to choice the right public address to be used (that of the outgoing interface).

As briefly mentioned by Alessio you may need PBR (policy based routing) to have specific hosts to use a specific link.

You can adapt this configuration template to your actual setup considering WAN1 and WAN2 your internet facing interfaces.

Hope to help

Giuseppe

[Kuldeep singh]

Thanks u so much Mr. Giuseppe,

I like advice only Experts like you,

But i still have some confusion with same problem :

1. Suppose I have three Internet connections. One ISP  gives 6 Mbps, another ISP gives 3 Mbps, and

    a third gives  1 Mbps.

    How much bandwidth any user will get inside LAN  during internet access, in case of ,

    if i configure Load Balancing or Load sharing????

2. I think Load sharing will work as Failover, mean to say, if one fails then remaining two will work or

   if two fails then remaining one will work in my case..   Am i right ??

[Giuseppe Larosa · Accepted solution]

Hello Kuldeep,

1)  each user is mapped on one internet facing link and can use as much as the speed of that link, the link bandwidth is shared between all users mapped to the same link. That's all the solution allows to use all the internet facing links but it does not provide guarantees to a single user

2)  failover will occur after detection, impacted users may have to reload the web page to trigger a new NAT translation, but NAT entries using the failed interface should be purged

Hope to help

Giuseppe

[Kuldeep singh]

Hi Giuseppe,

One more thing,  if i configure Load sharing with 3 ISP over cisco 1841 router then

how can i check particular user's internet taffic for Inbound and Outbound.

I mean to say, if user (172.25.162.5) access any website then

which isp's (A or B or C) traffic to come in and if same user send mail /upload or

any outbound traffic then which ISP's traffic is going out...

Network Diagram=>  Cisco 1841--------Cisco 3560-------------cisco 2960 --------------user

which command is needed for that and can i check same things on Cisco 3560 core switch ????

[Giuseppe Larosa]

Hello Kuldeep,

show ip nat translations on the C1841

show ip nat trans | inc 172.25.162.5

the C3560 will never know what provider is used for a specific user as NAT is performed on the C1841

Hope to help

Giuseppe

[Kuldeep singh]

Hi Giuseppe,

Check my answers which is Highlighted with red colour, if it is wrong , plz correct it=>

Multilink PPP (Works on Serial Port):

1. we can merge multiple T1/E1 links between two Router for Point to point Connectivity     Yes

2. we can merge multiple T1/E1 Links terminated over Router for internet access    Yes

3. I heard that Multilink Bundling works only on same ISP provider Links , not for Different ISP    Yes  or  No

Etherchannel ( works on Ethernet Port):

1. we can merge multiple Ethernet(Fe,Ge) links between two Switch or Router.        Yes (between two switch)      No (between two router)

2. can we merge multiple Ethernet(Fe,Ge) links terminated over Router for internet access   No

  ( This is related to my current Post, does cisco not provide any solution for this  )

Secondly,  I am planning to buy 1 Gbps internet link over fibre for internet access and its handoff is ethernet.....

I have checked all cisco router's throughput limit and last limit is 400 mbps. then

Plz suggest me which Router model is good for 1 Gbps connection ?   is it Possible with cisco ??

[Giuseppe Larosa]

Hello Kuldeep,

A) multilink PPP

A.1  yes

A.2   no you cannot configure ML PPP if the two links are terminated on different ISPs or different routers on ISP side

ML PPP requires that involved links are terminated in the same pair of devices because it requires appropriate configuration

B)  FE/GE bundle

1  yes between switches,  between routers only on etherswitch modules not on routed interfaces ( for ISR routers)

2  Again if the links are in different technologies or terminated on different ISP or different devices you cannot bundle them as for ML PPP a FE/GE bundle requires configuration between a pair of network devices.

C) 1Gbps link

C7200 NPE-GE2  (Eos) or C3945E or ASR 1000 but it is more expensive. Full support for each packet size in ASR 1000. The first two are enough with normal internet traffic mix.

Hope to help

Giuseppe

[Kuldeep singh]

Hi Giuseppe,

Here i am talking about only public internet link, plz not consider point to point:

1. we can aggregate Multiple same ISP links for internet access

   which have serial handoff through Multilink PPP.                            Yes

2. We can not aggregate Multiple same ISP links for internet access

   which have Ethernet handoff through Etherchannal or Else.             Yes 

If i am wrong plz correct me ...........

[Giuseppe Larosa · Accepted solution]

Hello Kuldeep,

1) yes requires same ISP and same router on ISP side

2) no generally speaking is less likely as it requires appropriate HW but it is still possible in a few cases

Hope to help

Giuseppe

[saashaa747]

 could you please help me about below scenario: I have 2 separate internet connection from two different ISP. please let me know I would like to use one of the connection for main internet connection and the other one in backup connection, so I would like that the second (backup) line will be used when the main Internet connection bandwidth is using completely (Its BW is full). if it is possible please let how I can implement this scenario and which devices are suitable for it. Thanks for your guidance in advance. Regards,