[ENet-discuss] enet & techniques

[celuyu celuyu]

Hello,

I've heard good things about enet; "enet's best.. Use enet, problem solved"
-- from some good coders. I've been looking forward to using enet for my
project.
I don't have a full understanding of low-latency networking concepts, and I
figured that with enet, I'd discover how to do things best as I went.
During my research to learn more on the subject, I came upon a little paper
titled "Beyond the LAN: Techniques from Networked Games for Improving
Groupware Performance."
It can be found here:
http://hci.usask.ca/publications/2006/game-networks.pdf
The paper was quite good for helping me to get a high level awareness of the
techniques that are out there, and it compares a bunch of the libraries,
including enet.
It did, however, raise some questions about enet. I do not mean for this
post to be about "who's best", but just to help me make a decision.
The paper presents a number of features which it states are only existent in
TNL and Raknet.
I realize that both are higher-level libraries, but this isn't an issue of
interface- it's of the underlying methods used for transport and latency
reduction.

There's a good number of other differences in the libraries, but I'm
concerned with Sections 4.1.3 through 5.1.

In particular,

Section 4.2.1, Combinations:
For instance, Priority, and Deliver at all costs:
The ability to have a "sequenced" policy: unreliable, but always in order.
"The reliable sequenced policy drops all late arriving reliable information
at the receiever."

Section 4.2.2, TNL's message-level reliability:
"As an example, consider the same scenario as above where a packet is lost
containing an unreliable movement message and a reliable ordered weapon fire
message. The movement message could simply be dropped since delivery is not
required, and the weapon fire message could be aggregated into the next
packet to be sent, which eliminates the need to resend the lost packet."

Section 4.3.2, The current state data policy.

Section 4.3.3, TNL's quickest delivery / QD policy:
The abilty to trade bandwidth for lower latency, like Quake3's networking
model. Can enet do this?

And importantly, how it all comes together:

Section 5.1, shows the possibily to choose the best combination of delivery
methods for the given message:
Reliable Unordered
Reliable Ordered
Unreliable Unordered
Unreliable Ordered
Unreliable Sequenced
Each combined with a priority, or QD.

As you can see in Section 5.1, a clear and logical diagram was drawn up
showing exactly which messages would require which kinds of transmission.
After reading this logical dissection of the combinations, it sounds great.
This appeals to me, as I can envision immediately which kind of
transmissions I'd use for each of my events. No single technique must make
the whole stream inefficient, because you can choose what's best for each
individual message.

I noticed that enet doesn't do many of these things. I realize that this
kind of feature analysis can often be one-dimensional, because it doesn't
account for coding technique: how you use the library. I consider it's
possible that enet doesn't do some of these things, because you go about
solving the problem some-other-way.

Does enet just have "another way of doing it?"
How can enet handle each of the combinations which were outlined?
Further, what's the best way to handle aggregation with enet?

- Celuyu
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.cubik.org/pipermail/enet-discuss/attachments/20060725/621b7130/attachment.htm