Virtual Link is a non-Physical connectivity or link. As we know OPSF must be connected with Backbone Area0 but sometime it becomes difficult due to some reasons. So there we required Virtual Links for logical connection to Backbone. Also known as logical link which uses in least cost path connectivity between routers or ABR or backbone/Non-backbone. A virtual link does not have ABR physical Connectivity to Backbone till to configure virtual link between non-backbone area and Backbone. In between two routers, a virtual link can be configured, that have an interface to a single common Transit/Non-backbone area but it can’t Read More …
Tag: Open Shortest Path First
OSPF Authentication
What is Authentication: Authentication is the mechanism of recognizing the identity of a user. Associating an incoming request with a set of identifying credentials is called Authentication. The credentials provided are compared to those in the database of the authorized user’s information register on a local operating system or somewhere remote. If the user is on white-list then he/she is allowed the access, otherwise the access is rejected simply. Types of OSPF Authentication OSPF supports two types of authentication i.e. Plain Text authentication and Message Digest 5 (MD5) authentication. As a message/packet required authentication for both destinations. Read More …
Hello Protocol
“A protocol used by Layer3 devices (like Routers) to discover neighbors and form adjacencies with each other” When a protocol process starts on a router, neighbors must be discovered and adjacencies must be established. Hello is a protocol which performs this duty. Hello protocol performs several functions, including but not limited to: It discovers neighbors (such as OSPF or IS-IS routers) It performs three-way handshaking to ensure bidirectional communication between the neighbors. It communicates information necessary for establishing whether an adjacency can be formed with a neighboring router After an adjacency is formed, it serves as a keepalive mechanism to Read More …
OSPF Timers (OSPF Intervals)
Routing protocol use Timers (Intervals) to keep all routers in a domain updated. Through the use of these timers, a routing protocol is able to maintain a stable neighbor relationship and ensure routes are propagated correctly. OSPF routing devices constantly track the status of their neighbors by sending and receiving Hello Packets to confirm whether each neighbor still is functioning normally. We can use these OSPF Intervals (OSPF Timers) to adjust the network convergence time in an OSPF network. Types of OSPF Timers: OSPF uses two types of OSPF Intervals (Timers): Tells the router after how long should it Read More …
Open Shortest Path First (OSPF)
Introduction OSPF is an open source Routing protocol that handles routing for IP traffic standardized in IETF RFC2328. OSPF is classified as an Interior Gateway Protocol (IGP). This means that it distributes routing information between routers belonging to a single Autonomous System. The OSPF protocol is based on link-state or SPF technology. It was designed mainly for the TCP/IP internet environment. Main focus was to produce a protocol that responds quickly to topology changes, with small amounts of control traffic. OSPF is a dynamic routing protocol. It quickly detects topological changes in the AS (such as router interface failures) and Read More …