Combining multiple connections from an ISP?

cisco_trooper · October 2009

Working on a new branch office deployment. The upload speeds required by the new office have brought up the idea of bonding multiple connections from a single ISP in order to increase upload bandwidth. It is my understanding at this time that these will be business class cable connections brought in on cable modems, and handed off to me over ethernet.

I have never bonded two ISP connections like this and quite frankly I can't figure out how to do it. It might be easier if I knew a technical name for this type of deployment. I've heard of people bonding T1 WICs (IMA..inverse multiplexing over ATM)...but never Ethernet.

Anyone have any suggestions/recommendations?

Forsaken_GA · October 2009

I call bonding two ethernet ports EtherChannel

I assume the problem for you here is that these are two layer 3 connections, so you can't really bond them in the traditional methods.

I don't know if you have the budget for it, but if it was an option, I think I'd rather deploy GLBP than fool with bonding two connections together like this.

ColbyG · October 2009

"Bonded" probably isn't the term you're looking for. You're talking about load-balancing across different ISPs, which will increase your overall bandwidth, but each flow will still be limited to the speed of a single ISP.

If that's what you're looking for, it can be done with two default routes, one pointing to each ISP. This will load balance your traffic, you can also configure load balanced NAT. Check out this link:

IOS NAT Load-Balancing with Optimized Edge Routing for Two Internet Connections - Cisco Systems

That should get you going in the right direction. I would also use the SLA configuration in that config so if one of your ISPs is down only the other ISP will be used.

ColbyG · October 2009

Forsaken_GA wrote: »

I call bonding two ethernet ports EtherChannel

I assume the problem for you here is that these are two layer 3 connections, so you can't really bond them in the traditional methods.

I don't know if you have the budget for it, but if it was an option, I think I'd rather deploy GLBP than fool with bonding two connections together like this.

You don't think GLBP would be overkill for this?

Forsaken_GA · October 2009

ColbyNA wrote: »

You don't think GLBP would be overkill for this?

That depends. If his budget will support it, then no

The ability to deploy redundancy and load balancing at the same time holds great appeal for me. I like my sleep.

ColbyG · October 2009

Forsaken_GA wrote: »

That depends. If his budget will support it, then no

The ability to deploy redundancy and load balancing at the same time holds great appeal for me. I like my sleep.

Yea, I know what you mean.

I don't think I've ever recommended GLBP to anyone. I guess that's because I've never used it in production.

cisco_trooper · October 2009

Yeah, people here are thinking in the ether-channel sense, but I'm thinking that isn't going to working coming in on two separate cable modems. I'm going to have to re-work all of this with them. I'm totally not a retard with BGP and all the gateway redundancy protocols. I'm just really curious if there is some other "bonding" technology because it is being thrown around pretty matter of factly right now.

ColbyG · October 2009

cisco_trooper wrote: »

Yeah, people here are thinking in the ether-channel sense, but I'm thinking that isn't going to working coming in on two separate cable modems. I'm going to have to re-work all of this with them. I'm totally not a retard with BGP and all the gateway redundancy protocols. I'm just really curious if there is some other "bonding" technology because it is being thrown around pretty matter of factly right now.

It has to be done at both ends, you can't just decide to throw Etherchannel (or anything similar) onto two ethernet links.

I don't know of a way to do what you're suggesting, other than the link I posted. You could look into load balancing devices, but I doubt they will accomplish much more than what you could do with a Cisco router.

Forsaken_GA · October 2009

cisco_trooper wrote: »

Yeah, people here are thinking in the ether-channel sense, but I'm thinking that isn't going to working coming in on two separate cable modems. I'm going to have to re-work all of this with them. I'm totally not a retard with BGP and all the gateway redundancy protocols. I'm just really curious if there is some other "bonding" technology because it is being thrown around pretty matter of factly right now.

Yeah, that's the traditional problem with bonding a connection, both ends need to support it. This is why Multilink PPP never real took off during the dialup heydeys, few providers wanted to put in the infrastructure to support it. It sounds like they're just giving you two layer 3 drops, and at that point, you're looking at load balancing/sharing as opposed to bonding the media. I like GLBP for simple load balancing situations, but I always prefer to do my traffic manipulation to multiple providers via BGP if at all possible, though I'd be pretty surprised at a cable provider willing to give you BGP tables

cisco_trooper · October 2009

Glad to hear everyone is having the same thoughts I'm having. This is why management should let the techs do the talking. I'm going to have to go back to the ISP and see if they'll even be able to route the static IP space over both links. Thanks guys....appreciate the second set of eyes.

tech-airman · October 2009

cisco_trooper wrote: »

Working on a new branch office deployment. The upload speeds required by the new office have brought up the idea of bonding multiple connections from a single ISP in order to increase upload bandwidth. It is my understanding at this time that these will be business class cable connections brought in on cable modems, and handed off to me over ethernet.

I have never bonded two ISP connections like this and quite frankly I can't figure out how to do it. It might be easier if I knew a technical name for this type of deployment. I've heard of people bonding T1 WICs (IMA..inverse multiplexing over ATM)...but never Ethernet.

Anyone have any suggestions/recommendations?

cisco_trooper,

I'm not sure how things work in the "business class cable connections" side but I understand that "residential class cable connections" is on a "shared bandwidth" basis. So the more customers/connections on the cable Internet segment, the lower the speed for each customer on that segment. So if you're going with the "single ISP" option, you might run into the ironic situation that your second cable link might "help" to bring your first cable link's speed down and depending on how many customers are already on that cable segment, possibly negate the "higher speed" goal of having two cable links. Also, since it's on a "single ISP" basis, you may not have true redundancy as far as backup links go since if that one cable ISP goes down, ALL links to that cable ISP may go down.

cisco_trooper · October 2009

I agree airman. Cable is definitely not my idea of corporate connectivity, however I have to consider the size of this particular office, their budget, and their bandwidth requirements. The purpose for the second link to my knowledge is only for increasing bandwidth...so I'll have to double check that it isn't shared bandwidth scenario. Good point.

Daniel333 · October 2009

Ill just throw in my $.02 here. We have a client with a T1 and a business grade comcast cable connection.

The t1 handles voice, citrix and their web server. QoS etc is setup. The cable internet is used for all the general web and file traffic. Works out pretty well, your youtubers can't mess anything critical up.

kristianbrown · October 2009

You could always load balance between the links based on traffic type. For example, voip and video through on of the links and all other through the other.

Else, I guess BGP would be your best bet.

SysAdmin4066 · October 2009

I'm thinking GLBP would work here, Etherchannel wouldnt work for this particular situation. Either GLBP, VRRP, or HSRP. Obviously GLBP would be best, but maybe you dont have the capability to do so. Expense wise, what are we talking here, just an extra router right?

ColbyG · October 2009

He said this is a branch office, I think recommending buying another router is overkill. Load-balancing two internet connections is relatively simple and definitely doesn't require two routers and a redundancy protocol.

Forsaken_GA · October 2009

ColbyNA wrote: »

He said this is a branch office, I think recommending buying another router is overkill. Load-balancing two internet connections is relatively simple and definitely doesn't require two routers and a redundancy protocol.

Bad engineer! Stop thinking like a manager!!!

Panzer919 · October 2009

kristianbrown wrote: »

You could always load balance between the links based on traffic type. For example, voip and video through on of the links and all other through the other.

+1 Exactly

Combining multiple connections from an ISP?

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