Geekzone: technology news, blogs, forums
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.

46 posts


# 21106 15-Apr-2008 22:19
Send private message

if you get too many tcp retransmissions to 1 destination,is it bad?what causes tcp retransmissions?what are the consequences?solution?

Create new topic
7 posts

Wannabe Geek

  # 123869 15-Apr-2008 23:01

If the host your communicating with sends you 4 packets with sequence #'s 10,11,12,13 if you successfully receive all data, the client sends an ACK back with sequence#14 (the next number), if the last two packets were dropped along the way or were corrupted the client would send an ACK back with seq#12 (signaling that it only received 10 & 11) this would then que the host to do a re-transmission of #12,13.  Yes it's bad, because tcp is inherently a latency laden protocol.  There's multiple causes, mostly network congestion.

186 posts

Master Geek

  # 123888 16-Apr-2008 04:17
Send private message

Different stages of a TCP connection will have different retransmission strategies and timeouts. For example, during the three-way handshake at the start of the connection, the retransmission characteristics are different than later in the connection.

Are you seeing the retransmission in data coming to you or being sent from you? Is this during the bulk data transfer, or during connection establishment/termination handshake?

For example, during the initial handshake, you may see multiple SYN+ACK packets from the server you are trying to connect to. Some TCP stacks have very aggressive retransmission at that stage. If you see a couple of those, especially if you are talking to a server on the other side of the globe, you have absolutely nothing to worry about. That's still quite normal.

If you are looking at the bulk transfer, and you see retransmission of some of the larger data packets then this indicates a pipeline-stall: The sending side had to stop streaming its data and retransmit. Normally, TCP will try to avoid that and tunes its send and receive windows to that end. Having retransmission occur anyway at that stage probably indicates intermittent packet loss or delay, caused by congestion somewhere along the way.

Create new topic

Switch your broadband provider now - compare prices

Twitter and LinkedIn »

Follow us to receive Twitter updates when new discussions are posted in our forums:

Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:

Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:

News »

OPPO Reno2 Series lands, alongside hybrid noise-cancelling Wireless Headphones
Posted 24-Oct-2019 15:32

Waikato Data Scientists awarded $13 million from the Government
Posted 24-Oct-2019 15:27

D-Link launches Wave 2 Unified Access Points
Posted 24-Oct-2019 15:07

LG Electronics begins distributing the G8X THINQ
Posted 24-Oct-2019 10:58

Arlo unveils its first video doorbell
Posted 21-Oct-2019 08:27

New Zealand students shortlisted for James Dyson Award
Posted 21-Oct-2019 08:18

Norton LifeLock Launches Norton 360
Posted 21-Oct-2019 08:11

Microsoft New Zealand Partner Awards results
Posted 18-Oct-2019 10:18

Logitech introduces new Made for Google keyboard and mouse devices
Posted 16-Oct-2019 13:36

MATTR launches to accelerate decentralised identity
Posted 16-Oct-2019 10:28

Vodafone X-Squad powers up for customers
Posted 16-Oct-2019 08:15

D Link ANZ launches EXO Smart Mesh Wi Fi Routers with McAfee protection
Posted 15-Oct-2019 11:31

Major Japanese retailer partners with smart New Zealand technology IMAGR
Posted 14-Oct-2019 10:29

Ola pioneers one-time passcode feature to fight rideshare fraud
Posted 14-Oct-2019 10:24

Spark Sport new home of NZC matches from 2020
Posted 10-Oct-2019 09:59

Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.

Support Geekzone »

Our community of supporters help make Geekzone possible. Click the button below to join them.

Support Geezone on PressPatron

Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.