What about networking?

November 16, 2008

Has been a long time since I last did a post. I was a lot busy and bored to mess with my blog. I descided to make clean a issue most l2j admins ignore: Networking.

Data number one:

iface                  Rx                   Tx                Total
eth0:          33.17 KB/s          329.82 KB/s          362.99 KB/s

Data number two:

Server Status:
—>  Player Count: 141/200
+–>  Object Count: 63820
+–>      AI Count: 42967
+…. L2Item(Void): 124
+………. L2Item: 19073
+……. L2Monster: 40103
+……… Minions: 3597
+.. Minions Groups: 2404
+……….. L2Npc: 3340
+………… L2Pc: 139
+…….. L2Summon: 10
+………. L2Door: 1001
+………. L2Char: 0
—>   Ingame Time: 8:22
—> Server Uptime: 16hrs 23mins 3secs
—>      GM Count: 3
—>       Threads: 62
RAM Used: 1374

What this means?

Send: 329 KByte/ Second

Receive: 33 KByte/ Second

Players Online: 141

329 KB / 141 = 2.3KByte/ Second

33 KB / 141 = 0.23KByte/ Second

This is the connection that players “suck” from the server. These numbers are peak numbers.

Lets translate it to KBit / Second, just multiply it with 8.

Send: 18Kbit

Receive: 1.8Kbit

So, whats the failure behind the ADSL connections most servers use?

First lets make clear that we talk about the majority of the ADSL-based servers. There are ADSL-based servers with 300+ players online. We will speak about those that can’t hold more than 50.

Why ADSL connections are slower?

ADSL connection from server to client does this path:
Server ->
Router ->
Area ISP Connection ->
Town ISP Connection ->
ISP Interconnection ->
National ISP Connection ->
International Connection 1 ->
International Connection 2 ->
International Connection 3 ->
National ISP Connection ->
ISP Interconnection ->
Town ISP Connection ->
Area ISP Connection ->
Router ->
Player

Dedicated server to client do this path:
Server ->
Datacenter Router ->
Datacenter Backbone Connection ->
Backbone ->
International Connection 1 ->
International Connection 2 ->
National ISP Connection ->
ISP Interconnection ->
Town ISP Connection ->
Area ISP Connection ->
Router ->
Player

Of cource, dedicated servers have faster connection to the international backbones, more direct because they are supposed to work this way. ADSL connections are not connecting directly because they are cheaper and they are targeted to browsing/downloading usage. There is no reason for a ADSL to connect directly to international backbones. This means that even if the route till the packets reach international, in case of the ADSL, will have about 100ms of latency carrying on it, where dedicated server would have 10-20ms. This also happen because a ADSL ISP, has a 8Gbit connection that is shared to 3 million ADSL customers or even more. A dedicated server most likely to have a 100Mbit pipe to 10 servers (thats how most good dedicated server companies work). So in fact a ADSL connection is much more oversold than a dedicated server connection, causing the connection to have a lot of traffic and this results to high latency. Maybe the latency is not really visible in most cases, 20ms doesn’t mean good latency in a LAN network but means good on a ADSL line. So don’t get tricked.

I spoke about International connections. I won’t speak about National connections. I know very good that most Greek ISPs (this also apply to other countries sometimes), have bad inter-connection between them. What this means? They do take great care on high quality connections to the out world, but don’t care enough care of the connections between them. So if your server is in the same ISP as your player’s then things are fine. You can hold about 100 players with a greek ADSL. But if your server is on different ISP than your player’s things become nausty and you might not hold more than 30.

This is not happening to discurage future admins from hosting their servers on a ADSL connection. This article is written tou courage you to move to a dedicated server as soon as possible, than keep being on a ADSL. Dedicated servers can be cheap and with high quality, so cheap that a ADSL is not worth. For example a small dedicated that can hold 500 players could cost arround 50 euro / month when a Greek ADSL 10/1Mbit costs arround 20 euro / month. The cost is so low that you don’t even need donations.

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