# Why are ISP's installing routers on my site when the feed is a form of ethernet already?

I'm connected to 3 ISP's right now. Two of them already have routers at my site, the third one announced me "they need to install some equipment" when I requested BGP session. I can only assume they need to install a Router, since that connection is now working fine, using the usual /30 net block for the connection, and the "last-mile" solution is not going to change since they only installed it last week and the BGP was in the contract from the beginning.

I simply don't understand this: the "feed" is already a form of ethernet. Even those they're using different technologies for the last mile, they're all entering the ISP router using an RJ45 WAN port. I assume the ISP router does something really important that can't be done by the Big Router on the other end of the connection. It must also be something that can hurt them if miss-configured, since they don't trust us (the client) to do the stuff on our router. And I'm not talking cheap throw-away routers here: One of the routers is Cisco 2800.

### Edit to add network details:

I'm connected to 3 ISP's, two over Radio links, one over Fiber Optic. One of the radio links is going to get dropped and the other radio link will be turned into fiber sometime next year. The fiber is 20 Mbit, radio 1 is 40 Mbit and radio 2 is 2 Mbit. I've got a /24 of provider independent address space. I'm not doing out-of-the ordinary stuff with my network, I'm overly connected because my network needs to be "up" all the time.

Do they really need a $2000 router at every customer site? Probably not. What it boils down to is that they are using equipment that is known and respected: using devices that are unlikely to fail supports compliance with their SLA, so they choose equipment that is well-known, dependable, and interoperable. As cable companies and other lower-cost providers continue to expand into business-class data services, it is entirely possible that traditional telco ISPs' on-premise equipment will start to get leaner in order to support more competitive pricing. I have seen plenty of offices that have a ~$100 DOCSIS 3.0 cable modem providing a 50 Mbps primary connection, alongside $1,000+ Cisco equipment serving as the demarcation point for a 1.5 Mbps T1 or MPLS connection from a telco. Of course, the slow telco connection is costing the business at least twice as much as the fast cable connection. Sure, the telco provides a better SLA, and the cable connection usually has slightly more latency and jitter, but you can guess which one is the primary WAN connection on the firewall... and you can guess which one the business would prefer to keep if the budget axe were to fall. • When I had a T1 through AT&T (many moons ago) they even required that we keep a separate phone line and they provided a modem which was connected to the console port on the router they provided in case the data connection went down for some reason (for remote troubleshooting). In the several years we had that T1, the one time it went down, just after midnight on New Year's Day, they had a technician on-site within an hour to fix it. Good luck getting that kind of support from cable providers these days. – Justin Scott Dec 1 '11 at 8:51 • The SLA + demarcation makes a bit of business sense: I do have "premium SLA" with the provider that installed the Cisco. They do react fast when something's wrong, and sending someone at my door usually involves two engineers, a car and specialist equipment that's probably more expensive then the car. I guess it pays to know for sure the problem is on there side, or the client's side. – Cosmin Prund Dec 1 '11 at 8:51 • In addtion, because it is THEIR router they have access to updaets and all the metrics in it - which helps them actually measure the lin quality. if you control the router, how do theyk now "you are down"? Or too stupid to configure your firewall properly. Extending a mesuring point to the customer gives them a way to measure line utilization, speed and error rates on the physical link. – TomTom Dec 1 '11 at 9:20 This is just normal practice... Example: I have two connections at our home office. One cable (60/20) and one isdn (20/1) The isdn ISP delivers one box that is everything in one: router, wlan and modem. The cable ISP delivers two boxes: a router and a modem. Both of these connections go into our office and connect to my zyxel router. I've talked to both of these ISP's for a while to understand what's going on. If you read their contracts, it mostly says that they will offer free service if the connection fails. Reading a bith closer it actually means that they will fix it.... up to the point of their equipment, from there on you're on your own. A second reason is for them to do offsite maintenance. While it just looks like a router these things are often also used for keeping statistics. This way if you say there is a problem they'll simply login to their equipment and magically fix it. And another reason would be that if you were so stupid to directly plugin a computer, the computer wouldn't get an external IP and be open to the net. But in the end, it never slows down your eventual connection, it will only make it faster and more reliable. and don't think it will limit your possibilities. With every setup I have encountered (even the all in one box) you can still grab the external IP and use every single damn port. Besides all the above entries; If there is a junction of suppliers, then the responsibility border of each supplier must be clear and definite and I suppose the mentioned ISP does that by using a separate router. Especially active units are very critical; as a minor change of one supplier or an inhouse technician servicing a shared unit may cause a major problem to a system which is in the responsibility area of another supplier. It eventually costs to all sides including the customer in terms of time and money. It's difficult to answer without knowing anything about your ISPs and your network setup. But you can just look at it from a simpler point of view: if you already have a router for each one of your two other ISPs, what's so strange about having another router for the third one, too? And even if what they want to do with their router could properly be done by your one, it could still make sense for them to bring their own router to your site, instead of having you configure yours. There could be technical reasons, or maybe they just want more control on how the connection is terminated at your end. • There's nothing strange about the third router, there's something strange with all three routers. I'm sure there must be something technical, because the ISP's are business after all: they would not install a$800 worth router in my room unless they absolutely, really need to. I don't have a problem with this setup, I just want to understand the "why". – Cosmin Prund Dec 1 '11 at 8:32