MY CCIE JOURNEY

U=Urgent Reserved 1|A|P|R|S|F

->If set , checks the urgent pointer field later in the header. That field indicates where you should start reading the data

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A=Ack Reserved U|1|P|R|S|F

->If set , indicates that the sender is acknowledging receiver from the partner


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R=Reset Reserved U|A|P|1|S|F

->If set, sender is refusing or explicitly closing the connection


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understanding these flags helps in understanding our tcp connections which are very much helpful in getting protocols like BGP for example .. can you imagine importance of Reset flag in BGP?

The Tcp Flags

we have


Reserved bits like U|A|P|R|S|F

U=Urgent Reserved when set on 1|A|P|R|S|F
A=Ack Reserved when set on U|1|P|R|S|F
P=Push Reserved when set on U|A|1|R|S|F
R=Reset Reserved when set on U|A|P|A|S|F
S=Syn Reserved when set on U|A|P|A|1|F
F=Fin Reserved when set on U|A|P|A|S|1

Tcp Functionality

-> Connection-oriented communications

->sequencing and acknowledgement

->windowing

->congestion avoidance and recovery

->specialised functions (aka flags)

->variable length header

->Recovery for lost packets

people who were following me or just watching my progress kept me mailing about the blog status . i was down with personal problems and was buried deep ! very deep .. iam just making out to brighter side of my life again and hence started with studies ...

i will be continuing with tcp / ip sessions and my notes as well

best regards