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Linksys Wireless-N Gaming Router WRT330N model review

12/05/10

Permalink 09:53:03 pm, by lano1106, 1605 words, 6921 views   English (CA)
Categories: TCP/IP, Hardware reviews, Video games

Linksys Wireless-N Gaming Router WRT330N model review

It is an ok Gigabit router with its wireless functionality working fine. However when connecting a PS3 on the router and let it test the router capabilities, the router fails the UPnP testing. In my opinion, this is inexcusable when you sell a product at premium price and you market it as a "gaming" router, you would expect the company to have tested it with all the mainstream consoles.

I have contacted Cisco/Linksys customer support chat service to report the problem and get assistance and basically, I have been told something like that the problem was my fault and that I had to change some obscure and unrelated WiFi settings to fix my problem.

I was not satisfied by the answer and I decided to see for myself why the PS3 is reporting a UPnP failure with that router.

2 tools have been required for the analysis.

  1. Wireshark
  2. An Ethernet hub

A hub is a piece of networking hardware allowing you to share an Ethernet link between more than 2 network devices. Those were common in the 90s when processing power and memory were expensive. Today they have been replaced by the more robust and powerful Ethernet switches. My setup has been to plug my PC between the Linksys router and my PS3 and let Wireshark running on my PC sniff the UPnP exchange between them.

Before going in the details of the PS3 UPnP test, I want to share some interesting details about the whole PS3 Internet testing which is close to be undocumented on the Internet

Testing Internet Connection:

It does it by doing a HTTP request on fus01.ps3.update.playstation.net.


GET /update/ps3/list/us/ps3-updatelist.txt HTTP/1.1
Host: fus01.ps3.update.playstation.net
Connection: Keep-Alive
Accept-Encoding: identity
User-Agent: PS3Update-agent/1.0.0 libhttp/1.0.0

HTTP/1.1 200 OK
Server: Apache
ETag: "4d8c4dbf774c6349ad778577e53bd8c7:1285037260"
Last-Modified: Tue, 21 Sep 2010 02:47:40 GMT
Accept-Ranges: bytes
Content-Length: 252
Content-Type: text/plain
Date: Mon, 06 Dec 2010 03:22:33 GMT
Connection: keep-alive

# US
Dest=84;CompatibleSystemSoftwareVersion=3.5000-;
Dest=84;ImageVersion=0000b437;SystemSoftwareVersion=3.5000;CDN=http://dus01.ps3.update.playstation.net/update/ps3/image/us/2010_0921_0215e26d1dadeb950471a9c3397a140a/PS3UPDAT.PUP;CDN_Timeout=30;

Test PSN connection:

It does so by establishing an HTTPS connection with auth.np.ac.playstation.net. Obviously since it is encrypted, I cannot comment much about it.

NAT Type testing.

The PS3 sends a series of STUN (Session Traversal Utilities for NAT) (I am mentionning STUN in another blog entry for the curious) requests to us.np.stun.playstation.net

So now, lets get back to the UPnP testing. Here is a short overview of the whole procedure:

  • Broadcast a request to find all network devices that are a InternetGatewayDevice
  • Query its capability by requesting a XML file
  • If the service WANIPConnection is supported, continue the test
  • Call GetExternalIPAddress to obtain the router public Internet IP address
  • Call AddPortMapping to open a public port on which all inbound traffic will be forwarded to the PS3

Here is how goes the exchange with the WRT330N router:


PS3 Broadcast:

M-SEARCH * HTTP/1.1
HOST: 239.255.255.250:1900
MAN: "ssdp:discover"
MX: 5
ST: urn:schemas-upnp-org:device:InternetGatewayDevice:1

2 seconds timeout. Retransmit the same request

After about 1.5 seconds after the 2nd retransmission, the router finally reply:

HTTP/1.1 200 OK
EXT:
SERVER: ipOS/7.2, UPnP/1.0, ipSSDPDevice/1.0
ST: urn:schemas-upnp-org:device:InternetGatewayDevice:1
LOCATION: http://192.168.1.1/root.sxml
CACHE-CONTROL: max-age=1800
USN: uuid:1C7AE0B4-AF9D-3FD9-AC27-04FAE3357DD5::urn:schemas-upnp-org:device:InternetGatewayDevice:1
Content-Length: 0

PS3 request this:

GET /root.sxml HTTP/1.1
HOST: 192.168.1.1:80

PS3 UPnP request:

POST /wipconn HTTP/1.1
HOST: 192.168.1.1:4444
Content-Length: 290
Content-Type: text/xml; charset="utf-8"
SOAPACTION: "urn:schemas-upnp-org:service:WANIPConnection:1#GetExternalIPAddress"

<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
<s:Body>
<u:GetExternalIPAddress xmlns:u="urn:schemas-upnp-org:service:WANIPConnection:1">
</u:GetExternalIPAddress>
</s:Body>
</s:Envelope>

Linksys Router:

HTTP/1.1 200 OK
SERVER: ipOS/6.8 UPnP/1.0 IGD/1.0
EXT:
Transfer-Encoding: Chunked

197
<?xml version="1.0" encoding="UTF-8" standalone="yes"?><soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" soap:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"><soap:Body><u:GetExternalIPAddressResponse xmlns:u="urn:schemas-upnp-org:service:WANIPConnection:1"><NewExternalIPAddress>xxx.xxx.xxx.xxx</NewExternalIPAddress></u:GetExternalIPAddressResponse></soap:Body></soap:Envelope>
0

2nd PS3 UPnP request:

POST /wipconn HTTP/1.1
HOST: 192.168.1.1:4444
Content-Length: 644
Content-Type: text/xml; charset="utf-8"
SOAPACTION: "urn:schemas-upnp-org:service:WANIPConnection:1#AddPortMapping"

<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
<s:Body>
<u:AddPortMapping xmlns:u="urn:schemas-upnp-org:service:WANIPConnection:1">
<NewRemoteHost></NewRemoteHost>
<NewExternalPort>3658</NewExternalPort>
<NewProtocol>UDP</NewProtocol>
<NewInternalPort>3658</NewInternalPort>
<NewInternalClient>192.168.1.109</NewInternalClient>
<NewEnabled>1</NewEnabled>
<NewPortMappingDescription>192.168.1.109:3658 to 3658 (UDP)</NewPortMappingDescription>
<NewLeaseDuration>0</NewLeaseDuration>
</u:AddPortMapping>
</s:Body>
</s:Envelope>

Linksys Router:

HTTP/1.1 200 OK
SERVER: ipOS/6.8 UPnP/1.0 IGD/1.0
EXT:
Transfer-Encoding: Chunked
151
<?xml version="1.0" encoding="UTF-8" standalone="yes"?><soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" soap:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"><soap:Body><u:AddPortMappingResponse xmlns:u="urn:schemas-upnp-org:service:WANIPConnection:1"></u:AddPortMappingResponse></soap:Body></soap:Envelope>
0

By looking the exchange it looks all good and in the router log, there is even an entry that shows that the Port mapping occured:


[INFO] Sun Dec 05 20:40:09 2010 UPnP renew entry 255.255.255.255 <-> 24.37.208.168:3658 <-> 192.168.1.109:3658 UDP timeout:-1 '192.168.1.109:3658 to 3658 (UDP)'

I initially believed that the error is the returned length of the router reply for the AddPortMapping request. It reports a length of 151 bytes but if you count them, I come to something around 340 chars! The GetExternalIPAddress call has the same problem. The reported size is 197 while in fact, I count around 410 chars!

However, a coworker of mine pointed out to me that the chunk size values are in hex as described in the RFC 2616. So I can only conclude that the problem comes from the PS3 that does not handle correctly HTTP chunked transfer coding in the context of UPnP exchange.

Another indication that the chunked transfer encoding in the replies is the culprit of the problem, it is that at the end of both exchange between the PS3 and the WRT330N is that the PS3 is sending back TCP RST segments to the router which means that the PS3 is closing its connection with the router before the router having finished to send its replies.

For your reference, here is an exchange with my new NetGear router, the WNDR37AV that works like a charm!


In less than 2 ms the reply to the M-SEARCH query comes back.

HTTP/1.1 200 OK
Cache-Control: max-age=1800
ST: urn:schemas-upnp-org:device:InternetGatewayDevice:1
USN: uuid:12345678-0000-0000-0000-00000000abcd::urn:schemas-upnp-org:device:InternetGatewayDevice:1
EXT:
Server: Linux/2.6.15-1.2054_FC5 UPnP/1.0 miniupnpd/1.0
Location: http://192.168.1.1:5555/rootDesc.xml

PS3 request this:

GET /rootDesc.xml HTTP/1.1
HOST: 192.168.1.1:5555

PS3 UPnP request:

POST /ctl/IPConn HTTP/1.1
HOST: 192.168.1.1:5555
Content-Length: 290
Content-Type: text/xml; charset="utf-8"
SOAPACTION: "urn:schemas-upnp-org:service:WANIPConnection:1#GetExternalIPAddress"

<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
<s:Body>
<u:GetExternalIPAddress xmlns:u="urn:schemas-upnp-org:service:WANIPConnection:1">
</u:GetExternalIPAddress>
</s:Body>
</s:Envelope>

Netgear reply:

HTTP/1.1 200 OK
Content-Type: text/xml; charset="utf-8"
Connection: close
Content-Length: 356
Server: Linux/2.6.15-1.2054_FC5 UPnP/1.0 miniupnpd/1.0
Ext:

<?xml version="1.0"?>
<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"><s:Body><u:GetExternalIPAddressResponse xmlns:u="urn:schemas-upnp-org:service:WANIPConnection:1"><NewExternalIPAddress>xxx.xxx.xxx.xxx</NewExternalIPAddress></u:GetExternalIPAddressResponse></s:Body></s:Envelope>

2nd PS3 UPnP request:
POST /ctl/IPConn HTTP/1.1
HOST: 192.168.1.1:5555
Content-Length: 644
Content-Type: text/xml; charset="utf-8"
SOAPACTION: "urn:schemas-upnp-org:service:WANIPConnection:1#AddPortMapping"

<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
<s:Body>
<u:AddPortMapping xmlns:u="urn:schemas-upnp-org:service:WANIPConnection:1">
<NewRemoteHost></NewRemoteHost>
<NewExternalPort>3658</NewExternalPort>
<NewProtocol>UDP</NewProtocol>
<NewInternalPort>3658</NewInternalPort>
<NewInternalClient>192.168.1.109</NewInternalClient>
<NewEnabled>1</NewEnabled>
<NewPortMappingDescription>192.168.1.109:3658 to 3658 (UDP)</NewPortMappingDescription>
<NewLeaseDuration>0</NewLeaseDuration>
</u:AddPortMapping>
</s:Body>
</s:Envelope>

Netgear reply:

HTTP/1.1 200 OK
Content-Type: text/xml; charset="utf-8"
Connection: close
Content-Length: 260
Server: Linux/2.6.15-1.2054_FC5 UPnP/1.0 miniupnpd/1.0
Ext:

<?xml version="1.0"?>
<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"><s:Body><u:AddPortMappingResponse xmlns:u="urn:schemas-upnp-org:service:WANIPConnection:1"/>
</s:Body>
</s:Envelope>

In conclusion, I am disapointed by the quality of the Linksys product and the lack of attention of details that the company did put in the QA before the release of that product since the UPnP bug could have been caught by a very simple test in less than 5 minutes. Apparently the bug is in the PS3 that does not support UPnP interaction with HTTP replies using chunked transfer coding but I was expecting to purchase a router compatible with my PS3 when I bought a gaming router. For that reason, I prefer the NetGear router.

Happy networking!

Comments, Pingbacks:

Comment from: RMP [Visitor] Email
Nice post. It helped me to find the issue why PS3 is hanging when we send media files via chunking..
PermalinkPermalink 09/02/11 @ 06:18

Comments are closed for this post.

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