Isp Router

[renon2000]

hello -

i was wondering how the internet sevice provider look like .

is there only one router in the isp which connect to the "back-bone" with optic fiber, or there are alot of routers is the isp which connect to the back bone ( with optic fiber) ?

there are hundreds of networks that connect to the isp,

that mean that they connected to the router who connected to the "back-bone"

and there are some kinds of lines - point to point , and others.

how all this customers are connecting to the same router ?

or maybe there are alot of routers,

or maybe it is one router with alot of virtual interfaces ?

hmm -

that it - thanks you for your answers :|

[thisisshanky]

An ISP can be considered as a collection of routers. Customers might need connectivity at various parts of a country, and hence, the same ISP will have different points of presence (POP) at many locations (cities, states) within the same country. each POP can be considered as an entry point into the ISP, which is essentially a high end router. Each POP router will be having high port density to connect to multiple customers. The routers internal to the ISP connecting between two POPS would be linked via fiber. These routers would be running BGP between themselves, to carry customer routes + other internet routes. ISPs usually keep a static route to the public network address assigned to the customer, and redistribute this route into BGP. So if there are 10 customers for this ISP in Newyork city, they will assign the required network addresses and provide connectivity via T1, ISDN, frame-relay or what ever means by which the customer needs connectivity for internet. All 10 customers connections may terminate at the same router. Security is definitely an issue, but with proper filtering and access-lists, Security loopholes can be blocked.

Many ISPs use MPLS in their backbone. They even use MPLS VPNS for separating each customer traffic as well as routing information. When you implement MPLS VPN on a router, each customer routing information is stored in a separate routing table (called VRF - virtual routing and forwarding) and each customer routing information is carried via MBGP (multiprotocol BGP) inside the service provider cloud.

[renon2000]

thanks

let say that there are 40 customers who want to connet to the internet

threw the isp pop. these customers want to connect with point to point lines,

this is mean the in the pop router the isp will create 40 virtual interfaces ?

how the isp will configure the pop router to enable those 40 customers to

connect to the internet through those point to point lines ??

thanks you again

bye--