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.
Question We run asr9001 with XR 6.1.3, and we have a very long delay to
login w/ SSH 1 or 2 to the device compare to IOS device. After
investigation, the there is 1s delay between the client KEXDH_INIT and
the server (XR) KEXDH_REPLY. After debug ssh serv...
Introduction The purpose of this document is to demonstrate the Open
Shortest Path First (OSPF) behavior when the V-bit (Virtual-link bit) is
present in a non-backbone area. The V-bit is signaled in Type-1 LSA only
if the router is the endpoint of one or ...
Hi, I am seeing quite a few issues with patch install and wanted to
share my experience and workaround to this. Login to admin via CLI, then
access root with the “shell” command Issue “df –h” and you’ll probably
see the following directory full or nearly ...