IP is best effort

eng_ahmedas

Hi All
I wish u r all in good health. could u please help me to understand what is meant by "IP is best effort protocol " ???
Thanks in advance
bye

dublin_101

eng_ahmedas wrote:

Hi All
I wish u r all in good health. could u please help me to understand what is meant by "IP is best effort protocol " ???
Thanks in advance
bye

it relies on TCP tp provide reliablility and flow control. this is achieved by

1. sliding windows (flow control)
2. sequencing number and acknowledgments (reliability)
3. synchronization (by way of establishing a virtual circuit).

so basically, if you know your layer 4 protocols, TCP and UDP, you'll know that TCP is slower, because it makes SURE that everything is being sent, and being sent in manner that the packets can be received and re-assembled accordingly!

ps...remember that IP on its own cannot do this, it relies on TCP for this!

EdTheLad

What is meant by best-effort is that TCP/IP does not reserve bandwidth on a path between 2 devices.If a link anywhere on the path between the two endpoints becomes saturated with traffic this can affect the IP service.
With other connection orientated protocols like FR and ATM a pvc is established end-to-end and specific guaranteed traffic rates can be defined.
So with IP since you cannot guarantee the available resources along the path it is considered best-effort.

dmaftei

eng_ahmedas wrote:

... what is meant by "IP is best effort protocol "

It means that the protocol does not garantee delivery of datagrams to the intended destination.

It does not mean that it relies on TCP to provide reliability (sorry, dublin...) IP couldn't care less what it carries as its payload (could be UDP, for instance.) When IP carries TCP, it's TCP that takes care of its own reliability; IP is still "best effort".

And it also does not mean "does not reserve bandwidth" (sorry ed...) What makes IP "best effort" is the lack of guaranteed delivery, not the lack of guaranteed resource availability.

Webmaster

dmaftei wrote:

What makes IP "best effort" is the lack of guaranteed delivery, not the lack of guaranteed resource availability.

Indeed, IP by itself is basically connectionless. Sending an IP packet is like sending a postcard. You mail it to an address and you hope the postal services 'route' it correctly and timely to the destination. TCP, a transport protocol, is used to control and manage the transport.

It does not mean that it relies on TCP to provide reliability

IP by itself not, but the "TCP/IP connection" does.

EdTheLad

Sorry Dmafei, ?Tell me what the difference is between lack of guaranteed delivery and the lack of available resources is?
Lack of guarenteed delivery?? Gremlins? maybe,theyve infiltrated the line and are stopping all usable data.

At the end of the day, the ask the customer what he thinks.
Best effort means no sevice guarantee full stop, if you have any other idea's about best effort maybe you should write an rfc.

dmaftei

ed_the_lad wrote:

...

Maybe you should calm down and express your disagreement with some civility, you might get an answer...

EdTheLad

Your right i wrote the reponse last night after about 10 beers sorry,
I ask myself what am i doing on a forum at 3am tanked up? maybe i shouldnt leave my pc on 24hr with such easy access to the net.

pannupandit

you are right ed_the_lad .Ip doesn't guarantee the delivery of datgrams and that can be only possible if the service is not available.