Need advice on a point-to-point wireless bridge failover

A

archivalbackup

Gawd
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Oct 12, 2007
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I know there are a lot of Cisco minded people lurking in the Forum, so I wanted to look for some been-there done-that experience.

I need to come up with a parts list for a wireless backup between two sites in case the primary 1Gb fiber link is cut.

History - there are currently two fiber pulls, but one is in the ground and keeps getting cut with backhoes (no location wire) and is currently cut (again). Currently load-balanced in an ether channel.

The two buildings are .5 Miles, direct line of site (may need mounting bracket to a pole).

Sustained transfer is 1800Kb with reasonable duration peaks from 3600Kb to 4600Kb. Applications are Database driven, latency sensitive, and very mission critical.

Upgrade path to N would be a plus, however dependability is a must. I am looking for suggestions on a Cisco point-to-point bridge that needs to stand up to heavy rain, fog, snow etc. Overkill such as high gain directional antennas is better than being cheap to make sure the backup link works when needed.

I also need to do some thinking on how I want to setup the fail over. Currently there is a fairly dumb HP switch at one of the sites, and a good Cisco at the other, so failover was setup with ether channel since the medium & speed were the same. Perhaps UDLD aggressive and tinker with the spanning tree (only the core of the network is routed at the moment). Worst case someone can always type in a command but this is not ideal.

So I need help coming up with a parts list, and experience/potential shortfalls for a wireless backup link.
 
For the bridges I would look at the Cisco 1300 and 1400 series. I've used both and they work well. The 1400 is pretty expensive but they are rock solid. I've got a pair that are just over a mile apart and are supporting voice as well as data over the link.

As for the fail-over scenario, I don't know enough to make a recommendation. I would imagine you could setup something in the routing tables on either end with different costs, should work.
 
archivalbackup said:
I know there are a lot of Cisco minded people lurking in the Forum, so I wanted to look for some been-there done-that experience.

I need to come up with a parts list for a wireless backup between two sites in case the primary 1Gb fiber link is cut.

History - there are currently two fiber pulls, but one is in the ground and keeps getting cut with backhoes (no location wire) and is currently cut (again). Currently load-balanced in an ether channel.
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I remember you telling me about this a long time ago, sucks that its happening again.

archivalbackup said:
Sustained transfer is 1800Kb with reasonable duration peaks from 3600Kb to 4600Kb. Applications are Database driven, latency sensitive, and very mission critical.
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A need for quality of service is pretty clear here. Priority queuing is a must. Implement it.

archivalbackup said:
Upgrade path to N would be a plus, however dependability is a must. I am looking for suggestions on a Cisco point-to-point bridge that needs to stand up to heavy rain, fog, snow etc. Overkill such as high gain directional antennas is better than being cheap to make sure the backup link works when needed.
Click to expand...
Well, if you want to go overkill... go with the ruggedized 1500. If not, I think the 1400 would be nice with a directional antenna and a rugged outdoor enclosure. Im not sure of many vendors that make this for our AP's, one of my customers is actually doing custom enclosures because no vendor will meet their desired spec.

archivalbackup said:
I also need to do some thinking on how I want to setup the fail over. Currently there is a fairly dumb HP switch at one of the sites, and a good Cisco at the other, so failover was setup with ether channel since the medium & speed were the same. Perhaps UDLD aggressive and tinker with the spanning tree (only the core of the network is routed at the moment). Worst case someone can always type in a command but this is not ideal.

So I need help coming up with a parts list, and experience/potential shortfalls for a wireless backup link.
Click to expand...
Honestly, route all the way down to the AP/routed port. Do IP sla with tracking to failover to the point to point if the fiber is down.

If you're going to go with STP, obviously RSTP and then aggressive UDLD will be required. If staying with 802.1D then aggressive isn't really required. PM me if you wanna talk more about this man.
 
Captain Colonoscopy said:
For the bridges I would look at the Cisco 1300 and 1400 series. I've used both and they work well. The 1400 is pretty expensive but they are rock solid. I've got a pair that are just over a mile apart and are supporting voice as well as data over the link.

As for the fail-over scenario, I don't know enough to make a recommendation. I would imagine you could setup something in the routing tables on either end with different costs, should work.
Click to expand...

Do you normally use the internal antenna in the 1310? Also, is 54Mbps realistic for a .5 mile link; I ran through the wireless planning tool and it spit out 1.77 Miles with a mounting height from the ground of 13'.

What bridge problems have you seen with the 1310 or 1410? According to all of the spec sheets and planning tools it is telling me that unless there is horrific noise in the 2.4Ghz band, the 1310 with integrated antenna bundled with a mounting kit is the way to go.

For the bystanders, a 1310 is ~ $770 and the 1410 is ~ $3400 (but comes with the mounting kit and 20' & 50' cables which add about $83 to the 1310).

Thanks!
 
archivalbackup said:
Do you normally use the internal antenna in the 1310? Also, is 54Mbps realistic for a .5 mile link; I ran through the wireless planning tool and it spit out 1.77 Miles with a mounting height from the ground of 13'.

What bridge problems have you seen with the 1310 or 1410? According to all of the spec sheets and planning tools it is telling me that unless there is horrific noise in the 2.4Ghz band, the 1310 with integrated antenna bundled with a mounting kit is the way to go.

For the bystanders, a 1310 is ~ $770 and the 1410 is ~ $3400 (but comes with the mounting kit and 20' & 50' cables which add about $83 to the 1310).

Thanks!
Click to expand...

I have only used the integrated antenna with both series. In my experience it is more than adequate. The only problem I've ever had was when a tree grew in front of one after about a year of working just fine. Cut the branch off and things started working again. :)

The mounting kits that Cisco sells are really good. You get everything you could possibly need to mount to your own mast or use the one that it comes with and bolt it to the wall. Even comes with this sealing goop tape to make all the exposed connections air/water resistant.

If you've only got 1/2 mile to contend with and have good line of sight then go with the 1310. Have you run around with your laptop in between to see what wireless is out there already? One advantage of the 1410 is the 5GHz radio in addition to the 4000dBi antenna. I swear I can feel my ears start to burn when I stand in front of one of those things....
 
I know it's not entirely within the scope of your post, but I've been using the BridgeWave AR80 as a failover for my Gig and 10Gig links. It's best when used building-to-building, operates at 80 GHz (FCC licensed) and gives you a full 1Gbit at very low latency (about the same as a fiber transceiver) so it's a perfect replacement for the occasional cut fiber. The problem here is that a BridgeWave link will run in the area of $35k-$50k for just the equipment. My longest link with the AR80X is right at 4.3 miles.

As for something in the 5GHz range, I have found that the Motorola Canopy does very well in the load-range you've given. We had several brands of 5GHz radios prior to deploying BridgeWave, including Cisco, and it seemed like every place there was a Canopy to contend with our signal was crap. The Canopy seems to handle the in-band interference better than anything else I've seen... although it's hard to beat having your own frequency.
 
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