14th Lecture - Networking

[k2s]

[quote name='riddle' timestamp='1320189478' post='3055224']
Endhi baa apesavu...
[/quote]

evvariki interest ledu baa.....
andaritho adithey adi dance.....
evvaru lenappudu adithey adi pichi..... adey....
ekkadoo ekanthanga adithey adi practice......

[ToughGuy]

[quote name='k2s' timestamp='1320190269' post='3055235']

evvariki interest ledu baa.....
andaritho adithey adi dance.....
evvaru lenappudu adithey adi pichi..... adey....
ekkadoo ekanthanga adithey adi practice......
[/quote]

neeku 100 sarlu seppaaaaaa ...nuvvu chesedi chsukuntooooooooo ellipooooo ..iam getting benifited ..tomorrow someone else will

[k2s]

[quote name='!!!! FeRRo !!!!' timestamp='1320193341' post='3055308']

neeku 100 sarlu seppaaaaaa ...nuvvu chesedi chsukuntooooooooo ellipooooo ..iam getting benifited ..tomorrow someone else will


[/quote]

[img]http://i46.tinypic.com/309otuc.gif[/img] antey...janalu oka ru iddaru anna thongi soothu unte... oka manam emi cheppedaniki meaning untadi kada ani [img]http://i46.tinypic.com/309otuc.gif[/img]

[ToughGuy]

[quote name='k2s' timestamp='1320202920' post='3055647']

[img]http://i46.tinypic.com/309otuc.gif[/img] antey...janalu oka ru iddaru anna thongi soothu unte... oka manam emi cheppedaniki meaning untadi kada ani [img]http://i46.tinypic.com/309otuc.gif[/img]
[/quote]

continue seyyi baa ....please

[k2s]

[quote name='!!!! FeRRo !!!!' timestamp='1320263965' post='3058070']

continue seyyi baa ....please
[/quote]

yeah setha ivvala next

[k2s]

Ok Guys . I am starting the lecture..continuation of BGP

Yesterday we talked about BGP finite state machine . i.e, how many states does BGP go thru...during its run.

Today we will talk about BGP Message types & BGP Packet types & formats .......




[color=#b22222]BGP Message Types[/color]

Four BGP message types are specified in RFC 1771, A Border Gateway Protocol 4 (BGP-4): open
message, update message, notification message, and keep-alive message.

The [color=#b22222]open message[/color] opens a BGP communications session between peers and is the first message sent
by each side after a transport-protocol connection is established. Open messages are confirmed using
a keep-alive message sent by the peer device and must be confirmed before updates, notifications,
and keep-alives can be exchanged.

An [color=#b22222]update message[/color] is used to provide routing updates to other BGP systems, allowing routers to
construct a consistent view of the network topology. Updates are sent using the
Transmission-Control Protocol (TCP) to ensure reliable delivery. Update messages can withdraw
one or more unfeasible routes from the routing table and simultaneously can advertise a route while
withdrawing others.

The [color=#b22222]notification message[/color] is sent when an error condition is detected. Notifications are used to close
an active session and to inform any connected routers of why the session is being closed.

The [color=#b22222]keep-alive message[/color] notifies BGP peers that a device is active. Keep-alives are sent often enough
to keep the sessions from expiring.

[k2s]

Next we will see about each packet format : open, updated, notification, and keep-alive message types

[k2s]

Read this - short notes on BGP packet formats

[url="http://www.pulsewan.com/data101/pdfs/bgp.pdf"]http://www.pulsewan.com/data101/pdfs/bgp.pdf[/url]

[tom bhayya]

[laddu123]

koncham windows servers meedha kooda classes teesukovachu gaa..

[k2s]

[quote name='laddu123' timestamp='1320275286' post='3058861']
koncham windows servers meedha kooda classes teesukovachu gaa..
[/quote]

naaku windows servers gurinchi telvadu bhayya........

[k2s]

BGP Path Attributes

The BGP attributes are a set of parameters used to keep track of route-specific information
such as path information, degree of preference of a route, NEXT_HOP value of a route, and

aggregation information. These parameters are used in the BGP filtering and route decision
process. Every UPDATE message has a variable-length sequence of path attributes. A path
attribute is a triple of the form <attribute type, attribute length, attribute value>. The attribute
type is a 2-byte field that consists of a 1-byte attribute flag and a 1-byte attribute type code.

[k2s]

[img]http://1.bp.blogspot.com/_5iS1PkhO0HU/TIFDogqLtsI/AAAAAAAAADs/j1ZkXtXkYOY/s1600/BGP+attributes.jpeg[/img]

[k2s]

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[k2s]

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