How I learned to love BGP communities, and so can you

BGP communities can be a powerful, but almost mystical thing.  If you aren’t familiar with communities start here at Wikipedia.  For the purpose of part one of this article we will talk about communities and how they can be utilized for traffic coming into your network. Part two of this article will talk about applying what you have classified to your peers.

So let’s jump into it.  Let’s start with XYZ ISP. They have the following BGP peers:

-Peer one is Typhoon Electric.  XYZ ISP buys an internet connection from Typhoon.
-Peer two is Basement3. XYZ ISP also buy an internet connection from Basement3
-Peer three is Mauler Automotive. XYZ ISP sells internet to Mauler Automotive.
-Peer four is HopOffACloud web hosting.  XYZ ISP and HopOffACloud are in the data center and have determined they exchange enough traffic amongst their ASN’s to justify a dedicated connection between them.
-Peer five is the local Internet exchange (IX) in the data center.

So now that we know who our peers are, we need to assign some communities and classify who goes in what community.  The Thing to keep in mind here, is communities are something you come up with. There are common numbers people use for communities, but there is no rule on what you have to number your communities as. So before we proceed we will need to also know what our own ASN is.  For XYZ we will say they were assigned AS64512. For those of you who are familiar with BGP, you will see this is a private ASN.  I just used this to lessen any confusion.  If you are following along at home replace 65412 with your own ASN.

So we will create four communities .

64512:100 = transit
64512:200 = peers
64512:300 = customers
64512:400 = my routes

Where did we create these? For now on paper.

So let’s break down each of these and how they apply to XYZ network. If you need some help with the terminology see this previous post.
64512:100 – Transit
Transit will apply to Typhoon Electric and Basement3.  These are companies you are buying internet transit from.

64512:200 – Peers
Peers apply to HopOffACloud and the IX. These are folks you are just exchanging your own and your customer’s routes with.

64512:300 – Customers
This applies to Mauler Automotive.  This is a customer buying Internet from you. They transit your network to get to the Internet.

64512:200 – Local
This applies to your own prefixes.  These are routes within your own network or this particular ASN.

Our next step is to take the incoming traffic and classify into one of these communities. Once we have it classified we can do stuff with it.

If we wanted to classify the Typhoon Electric traffic we would do the following in Mikrotik land:

/routing filter
add action=passthrough chain=TYPHOON-IN prefix=0.0.0.0/0 prefix-length=0-32 set-bgp-communities=64512:100 comment="Tag incoming prefixes with :100"

This would go at the top of your filter chain for the Typhoon Electric peer.  This simply applies 64512:100 to the prefixes learned from Typhoon.

In Cisco Land our configuration would look like this:

route-map Typhoon-in permit 20  
match ip address 102  
set community 64512:100

The above Cisco configuration creates a route map, matches a pre-existing access list named 102, and applies community 64512:100 to prefixes learned.

For Juniper you can add the following command to an incoming peer in policy-options:

set community Typhoon-in members 64512:100

Similar to the others you are applying this community to a policy.

So what have we done so far, we have taken the received prefixes from Typhoon Electric and applied community 64512:100 to it.  This simply puts a classifier on all traffic from that peer. We could modify the above example to classify traffic from our other peers based upon what community we want them tagged as.

In our next segment we will learn what we can do with these communities.

WISPS growing up in the tower industry Part 1

As more and more Wireless ISPs (WISPS) get into licensed microwaves, bigger antennas, and fiber up the tower (FUTT) they are getting into an arena typically reserved just for the Cellular and broadcast folks.  This can result in an overwhelming amount of things to deal with.

If you are renting space on a commercial tower managed by a regional or national company such as American Tower (ATC) you will run into things like application fees, engineering studies, and closeout documents to just name a few. Once you have your notice to proceed (NTP), the real work begins.

During your negotiation phase, and in your contract, you should have a center line on the tower.  This states the center line on the tower where your equipment is mounted.  An example is if your centerline states 200, on most contracts that means you have something like 5 feet above that and 5 feet below that.  Think of it as a window.  You have a window of 195-205′ on the tower for your equipment to fit in.

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Centerline example. Photo courtesy of Michael Pelsor

The equipment you put on the tower was specified in the engineering phase of the paperwork.  Model numbers of mounts, antenna models, and all that are decided before the first piece of equipment is ever put on the tower. This is very important to adhere to because many tower companies will require a closeout procedure.  This normally includes pictures of your equipment and how it’s mounted, pictures of what is called a tape drop, and other things.

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Tape Drop Pic courtesy of Michael Pelsor

The sheer amount of things to think about on a commercial tower with multiple tenants could extend this blog post on for a long time. But, one of the biggest things to consider is when you are installing how your cable runs, antennas, etc. are in relationship to other equipment.  Are your cables somewhere they might be stepped on by someone passing your equipment to get to theirs? Does your equipment cross mounts which may be removed later or modified?

In the second part of this series we will talk about some of the higher-end tools which may save you tons of time, thus paying for themselves rather quickly.

Open Source Box Design

One of the biggest challenges WISPs and anyone deploying wireless gear is power and distribution.  I have put together a checklist for purchasing items to make a standard box MTIN would deploy. This is not designed to be a how-to, but rather a “What to buy” guide.

Link to the PDF (7Meg Download)

Throughout this documents I make notes based upon experience. As with anything, these are not hard rules. They are meant to be guidelines to follow. Please adapt to your uses. For example, if you don’t have any non-cambium radios you don’t need the POE injectors found on page 5.

If you find this document useful please feel free to send your thoughts, beer money, or other admiration. Links to http://www.mtin.net/blog are always appreciated, as well as twitter ( @j2sw ) or facebook follows (http://www.facebook.com/mtinnet )are always appreciated.   If you reproduce any parts of this Open Source document please give credit to the original source.

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Box in deployment. Fiber has not been dressed so don’t worry it gets better protected.

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Basic no frills box with 2 PacketFlux gigabit injectors

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Getting the most out of your climbs

I have been wanting to write this article for awhile. When the topic is fresh in my mind I am usually too tired from a day of climbing. By the time things get around the lessons learned have escaped me. So, after a day of being in the sun on a 150 foot monopole I figured I would share some best practices.  These are aimed toward the WISP who wants to maximize their climbs.

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1.Tighten sector brackets on the ground and other bolts.  If it is holding it to the sector tighten it. The idea is the climber wants to be able to position the antenna against the mounting pole as easily as possible without needing extra hands.  Sometimes having both hands free is a challenge.  If you want to adjust downtilt on the ground the following links can help speed up the process. This is not necessary nor is it a requirement.  It just is one less thing to do in the air. Some helpful Links:

Proxim Downtilt Calculator

Wisp-Router downtilt calculator

I am planning on another blog article about downtilt calculations and my thoughts. We will go into this in a future post.

2.For Wireless backhaul shots in the 0-7 mile range use google earth.  Draw a line between the two points and use two reference points to get in the neighborhood.  By looking at the below screenshot I know to align my path over the edge of the building almost at the base of the tower.  This helped me determine mounting location and get a pretty close aim. You can get fancy with compasses, GPS alignment devices, and other high-tech toys, but people are typically visual people.  Having a reference point is easier on the mind than having a number like 121 degrees off north.  Microwave shots are a different beast so don’t lump tight beamwidth licensed links into the above statement.

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3.Don’t get too hung up on labels.  Instead I like to color code things.  If I am putting up 3 sectors I will get some colored tape and label them with a blue piece, a red piece, and a green piece.   This way if the client wants to have a sector facing north We have the software labeled blue.  I can identify color and tell the ground crew I faced the blue sector north. Makes things easier in the high stress environment of being hundreds of feet in the air. The cellular companies have some standardized labeling of their sectors:

Alpha is the North FACING vertical antenna on the cell tower
Beta is the Southeast FACING vertical antenna on the cell tower
Gamma is the Southwest FACING vertical antenna on the cell tower

I would suggest come up with a SOP for all your tower deployments, but be flexible.  Due to the various mounting locations it’s not always prudent to cookie cutter a WISP deployment like the cellular folks do.  I have installed gear on towers where you have a small corner of a rooftop or grain facility.  Due to other things being up there, the fact you are trading service or paying very little, your mounting options may be limited.

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4.On a related note color code everything. If you use colored tape, make sure to match the ethernet cables going to the sectors.  This way it is easier to identify the cable going to the sector. This also helps in easier identification of where things are plugged in.

5.There are six phases of the a WISP deployment.
Stage one- assembly and staging
Stage two – Mounting radio equipment and antennas
Stage three – Connecting power and connectivity.
Stage four – Physical adjustment and tuning
Stage five – Testing and tweaking
Stage six – cleanup and zip up

Think about each of these.  This will be another future blog post.

6.Have a plan of action.  Have a flexible order of doing things. Be able to adjust this on the fly due to various factors.  Sometimes is makes sense to mount the sectors, backhauls, and any other boxes at the top.  Once you have them mounted then make the connections.  Other times it may make sense to run the cable when you mount the device.

7. Have a loadout of specific tools in a bucket or tool pouch.  I like to include the following:
Knife – Automatic or assisted opening
Crescent wrench
Super-88 Tape
Zip ties
Phillips Screwdriver
Flat Screwdriver
Slip Joint pliers
Other tools such as ratchet wrenches, different sized tools, power tools, etc. are handy, and can make life easier. However, the above tools will allow you to 90% of what you need to do to install or remove most WISP equipment.  The flat screwdriver can be used to pry things loose or for leverage.

8.If you can do it on the ground do it.  Terminating and testing cat-5 is easier on the ground than 150 feet in the air.

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9. Train the ground crew to think about how this affects someone on the tower.  Most of the time folks don’t have the luxury of platforms. So they are hanging off the tower in awkward positions.  Doing a pull with 3 sectors attached to a load line might seem like you are saving time, but it might make things complicated for the climber.  Sometimes, 3 pulls might make their life easier.  They only have to deal with one thing at a time.  They aren’t fighting trying to unhook multiple antennas or figuring out what is what.  This is where straps come in very handy. A strap allows a climber some extra flexibility to move things around and position them better.

10.Have a checklist of sorts.  This can be a running thing as you go along.  I routinely tell the ground crew to remind me to do this.  If you have someone writing this stuff down they can read it back to you before you come down.

There are a great variety of tools, tricks, and ways of putting stuff on the tower.  Many people have their own ways of doing things.  These are just some of the best practices I have come up with through experience. We could debate tape vs zip ties and other things for hours.  Please leave comments and some tips that make your life easier.

 

MTIN WISPA Announcement

MTIN would like to announce some exciting new services for ISPs and network operators

The first is Midwest Internet Exchange ( www.midwest-ix.com )

MidWest-IX has created a peering fabric we are expanding to data centers focused on the needs of WISPs and network operators such as yourself. Peering can be a valuable, and cost-effective solution for your ISP. MidWest-IX has created a solution based around those needs.

We are tailoring and providing these services to the WISP community as a way of making everyone stronger. WISP operators need advantages. MidWest-IX can provide lower latency to content providers such as Netflix. MidWest-IX can cut down on transit costs through peering. We are also creating an ever-growing marketplace for members to provide redundancy, market goods and services to each other, and create a WISP peering cloud. We have many more benefits of an exchange listed at: http://www.midwest-ix.com/benefits.html

We have exchange services available at:

350 East Cermak Chicago Illinois
733 West Henry Street Indianapolis Indiana
401 North Shadeland, Indianapolis Indiana
900 Walnut St. Louis Missouri
535 Scherers Court Columbus, Ohio

If you are a WISP in Indiana, Ohio, Illinois, Kentucky, Michigan, or Missouri contact us on how we can leverage the exchange to help your business. Other locations planned for 2015.

Our next announcement includes services in several Data Centers.

MTIN in cooperation with Midwest Internet Exchange (M-IX) offers co-Location, bandwidth, peering, transport, and managed services.

Do you have a need for circuit termination, server/router space, or peering in any of the above locations? Let us put together a managed solution for you. MTIN can handle the ins and outs of cross-connects, facilitating ports to the exchange fabric, and other data center needs. A data center can be an intimidating thing. Let us take the guesswork out of it for you.

Services Include
-Bandwidth (let our experts provide unique and out-of-the-box solutions)
-Transport
-Cross connects and cable landings
-Off-site backup and DR
-Co-location (TierIV and basic Co-location)
-Connections to 3rd Party networks such as Internet2
-BGP Peering

MTIN provides xISP consulting and backend solutions. BGP, OSPF, routing, DNS, network engineering, and other services. Talk to us how we can put together a complete solution to optimize your network. Our Engineers can design a cost-efficte solution that fits you and your needs.

Contact us:

Web: www.mtin.net
Web: www.midwest-ix.com
e-mail: support@mtin.net
Tel: 317.644.2224