Cheatsheet: Difference between revisions
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= TCP |
= TCP = |
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*Congestion Control |
*Congestion Control |
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- If sender receives four acknowledgments with same value (three duplicates) |
- If sender receives four acknowledgments with same value (three duplicates) |
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- Segment expected by all of these Ack is resent immediately |
- Segment expected by all of these Ack is resent immediately |
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*Persistence Timer |
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- Issue of Deadlock created by Lost Ack, used to reset Window size 0 advertized earlier, is resolved by this timer |
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- Sending TCP sends a special segment(1 byte of new data) called Probe, causes the receiving TCP to resend Ack |
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- If no reply, another probe is sent and value of persistence timer is doubled and reset |
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- Sender continues sending probes, doubling, resetting value of persistence timer until it reaches a threshold(generally 60s) |
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- After that the sender sends one probe segment every 60s until the window is reopened |
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= VPN Messages = |
= VPN Messages = |
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