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Showing posts from November, 2011

SADDA HAQ

How to do Loopback Tests for T1/56K Lines

How to do Loopback Tests for T1/56K Lines :-   Introduction When a serial line does not come up as it must, the best way to troubleshoot the circuit is to perform loopback tests. Loopback tests allow you to isolate pieces of the circuit, and test them separately. Begin loopback tests on the customer premises with channel service unit/data service unit (CSU/DSU) loopback tests. Then proceed on to loopback tests that involve the telco or provider. Prerequisites Requirements There are no specific requirements for this document. Components Used The information in this document is based on Cisco IOS® Software Release 12.0. Conventions Refer to Cisco Technical Tips Conventions for more information on document conventions. Background Information Two kinds of loopback tests can be used to isolate problems on the serial link: software loopbacks and hardware plug loopbacks. Whether it is an internal or external CSU/DSU, you can do both software and hardware ...

OSPF (Open Shortest Path First )

Open Shortest Path First Open Shortest Path First (OSPF) is a routing protocol developed for Internet Protocol (IP) networks by the Interior Gateway Protocol (IGP) working group of the Internet Engineering Task Force (IETF). The working group was formed in 1988 to design an IGP based on the Shortest Path First (SPF) algorithm for use in the Internet. Similar to the Interior Gateway Routing Protocol (IGRP), OSPF was created because in the mid-1980s, the Routing Information Protocol (RIP) was increasingly incapable of serving large, heterogeneous internetworks. This chapter examines the OSPF routing environment, underlying routing algorithm, and general protocol components. Background OSPF was derived from several research efforts, including Bolt, Beranek, and Newman's (BBN's) SPF algorithm developed in 1978 for the ARPANET (a landmark packet-switching network developed in the early 1970s by BBN), Dr. Radia Perlman's research on fault-tolerant broadcasting of routing inform...