About router's connections

[Man-wai Chang]

What would a loosen LAN plug at one of the router wired LAN port affect
its wireless connections?

Are they supposed to be independent of each other?

 

[Paul]

What would a loosen LAN plug at one of the router wired LAN port affect
its wireless connections?

Are they supposed to be independent of each other?

What symptoms are you seeing ?

WiFi
MAC/Phy/Radio
|
|
WAN --- Router ----------- Switch ---- LAN RJ45
RJ45 Chip Chip ---- LAN RJ45
(A processor) ---- LAN RJ45
---- LAN RJ45

Paul

 

[Man-wai Chang]

Are they supposed to be independent of each other?

What symptoms are you seeing ?

Your diagram is correct. The router is Asus WL-530G.

Symptom: Failed to reach some but *NOT ALL* websites.

Solution: Re-sat the plug and all problems went away.

 

[Paul]

Your diagram is correct. The router is Asus WL-530G.

Symptom: Failed to reach some but *NOT ALL* websites.

Solution: Re-sat the plug and all problems went away.

Does the router have a log it keeps ? Look in
the log and see what events it recorded.

The router certainly has the ability to filter
out packets, for whatever reason. Then the question
would be, why would the router do that ?

The router software, inside the main processor, can
have some expectations about the packets it handles.
These would be examples of filtering operations, intended
to make the router more resistant to abuse from outside.

http://en.wikipedia.org/wiki/Twinge_attack

http://en.wikipedia.org/wiki/Stateful_Packet_Inspection

And because software is involved, just about anything
could be happening, if there is a bug in the router code.

Paul

 

[Man-wai Chang]

Does the router have a log it keeps ? Look in

the log and see what events it recorded.

Nothing adnormal. There was a strange entry that port-forwarded 50054 to
svchost.exe of my client PC.

The router software, inside the main processor, can
have some expectations about the packets it handles.
These would be examples of filtering operations, intended
to make the router more resistant to abuse from outside.
http://en.wikipedia.org/wiki/Twinge_attack
http://en.wikipedia.org/wiki/Stateful_Packet_Inspection
And because software is involved, just about anything
could be happening, if there is a bug in the router code.

The wireless side of the router should NOT be affected by wired
connection and vice versa, shouldn't it?

Maybe cheap routers don't completely separate the two circuits....

--
@~@ Might, Courage, Vision, SINCERITY.
/ v \ Simplicity is Beauty! May the Force and farces be with you!
/( _ )\ (x86_64 Ubuntu 9.10) Linux 2.6.39.1
^ ^ 17:27:01 up 1:36 0 users load average: 1.02 1.07 1.05
ä¸å€Ÿè²¸! ä¸è©é¨™! ä¸æ´äº¤! ä¸æ‰“交! ä¸æ‰“劫! ä¸è‡ªæ®º! è«‹è€ƒæ…®ç¶œæ´ (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

 

[Paul]

Nothing adnormal. There was a strange entry that port-forwarded 50054 to
svchost.exe of my client PC.


The wireless side of the router should NOT be affected by wired
connection and vice versa, shouldn't it?

Maybe cheap routers don't completely separate the two circuits....

WiFi
^
|
|
v
WAN <----> Router <----> LAN

I agree, that the three sides should not affect one another.

There isn't a circuit as such. As far as I know, the packets
are stored in router memory, and the router examines the
headers, and decides what to do with them. The home router
may not be capable of "wire speed" routing. Only the switch
chip on the LAN side is capable of good performance (From LAN
port to LAN port).

On the site that reviews routers, they don't even keep a table
of LAN to LAN transfer speeds, instead choosing to measure
LAN to WAN and WAN to LAN transfer speeds (because those
depend on the processor and its firmware).

Paul

 

[Man-wai Chang]

I agree, that the three sides should not affect one another.

.... snipped ...
On the site that reviews routers, they don't even keep a table
of LAN to LAN transfer speeds, instead choosing to measure
LAN to WAN and WAN to LAN transfer speeds (because those
depend on the processor and its firmware).

It's really weird.... time to experiment with the bad plugging?

--
@~@ Might, Courage, Vision, SINCERITY.
/ v \ Simplicity is Beauty! May the Force and farces be with you!
/( _ )\ (x86_64 Ubuntu 9.10) Linux 2.6.39.1
^ ^ 18:22:01 up 2:31 0 users load average: 1.06 1.06 1.05
ä¸å€Ÿè²¸! ä¸è©é¨™! ä¸æ´äº¤! ä¸æ‰“交! ä¸æ‰“劫! ä¸è‡ªæ®º! è«‹è€ƒæ…®ç¶œæ´ (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

 

[Man-wai Chang]

Nothing adnormal. There was a strange entry that port-forwarded 50054 to

svchost.exe of my client PC.

I think this entry was created by the uPnP function of the router. After
disabling it, the entry no longer appeared!

--
@~@ Might, Courage, Vision, SINCERITY.
/ v \ Simplicity is Beauty! May the Force and farces be with you!
/( _ )\ (x86_64 Ubuntu 9.10) Linux 2.6.39.1
^ ^ 20:31:01 up 4:40 0 users load average: 1.02 1.06 1.07
ä¸å€Ÿè²¸! ä¸è©é¨™! ä¸æ´äº¤! ä¸æ‰“交! ä¸æ‰“劫! ä¸è‡ªæ®º! è«‹è€ƒæ…®ç¶œæ´ (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

 

[GlowingBlueMist]

It's really weird.... time to experiment with the bad plugging?

I have had a loose cable on a LAN port which resulted in excessive
errors and retransmissions. The throughput for all LAN ports and the
wireless feed were affected as well sinced they were all connected
together by the router's internal bridge.

Some routers use a software bridge (along with a increase in router CPU
loading) while others use a hardware bridge chip. One MicroTic router I
recently worked on had both a hardware bridge chip and a software bridge
allowing you to use either, neither, or both depending on what you
wanted to do with the LAN and wireless ports.

 

[Man-wai Chang]

There isn't a circuit as such. As far as I know, the packets

are stored in router memory, and the router examines the
headers, and decides what to do with them. The home router
may not be capable of "wire speed" routing. Only the switch
chip on the LAN side is capable of good performance (From LAN
port to LAN port).

I begin suspect that it's the uPnP function that was causing the issues.
I am still *NOT* sure whether the loosen plug was the "catalyst".

--
@~@ Might, Courage, Vision, SINCERITY.
/ v \ Simplicity is Beauty! May the Force and farces be with you!
/( _ )\ (x86_64 Ubuntu 9.10) Linux 2.6.39.1
^ ^ 21:01:01 up 5:10 0 users load average: 1.06 1.07 1.09
ä¸å€Ÿè²¸! ä¸è©é¨™! ä¸æ´äº¤! ä¸æ‰“交! ä¸æ‰“劫! ä¸è‡ªæ®º! è«‹è€ƒæ…®ç¶œæ´ (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

 

[Paul]

That looks right, but shouldn't the Waif be connected to the switch
chip? It is a part of the LAN.

I supposed it depends on whether you consider the diagram to be physical
or logical

In the hardware, a LAN packet can't make its way to the Wifi, without
the router chip processing it. And as far as I know, they're separate
subnets, with a different set of IP addresses on the Wifi, than
are used on the switch LAN chips. So the router does its routing
function (logically) amongst three items.

But for local traffic, like if LAN_#1 wants to talk to LAN_#2,
that can be done without the router finding out. And that is
how LAN to LAN can be wire speed, limited only by the internal
design of the switch chip.

But once the router chip becomes involved, it is a rate limiting
step. The Wifi also has limits, and it's hard for me to guess whether
all Wifi routers will be limited by the Wifi part, or by the processing
that goes on in the router.

My first wired router, when the packets go to the router chip, it
was slow as molasses. My WAN to LAN was around 3MB/sec. More modern
equipment can do better than that.

I don't own a Wifi router like the one in the diagram. I have a couple routers,
but they're wired and don't have wireless. With regard to IP addresses, the
info there is from reading other people's posts.

Paul

 

[david]

I supposed it depends on whether you consider the diagram to be physical
or logical

In the hardware, a LAN packet can't make its way to the Wifi, without
the router chip processing it. And as far as I know, they're separate
subnets, with a different set of IP addresses on the Wifi, than are used
on the switch LAN chips. So the router does its routing function
(logically) amongst three items.

I believe that the WiFi and wired ports are on the same subnet in most
cheap consumer grade switches. At least on the ones I have.

 

[Man-wai Chang]

And because software is involved, just about anything

could be happening, if there is a bug in the router code.

Another confusion is the full testing of IPv6 lately.

--
@~@ You have the right to remain silence.
/ v \ Simplicity is Beauty! May the Force and farces be with you!
/( _ )\ (x86_64 Ubuntu 9.10) Linux 2.6.39.1
^ ^ 20:35:01 up 1 day 4:44 0 users load average: 1.08 1.06 1.05
ä¸å€Ÿè²¸! ä¸è©é¨™! ä¸æ´äº¤! ä¸æ‰“交! ä¸æ‰“劫! ä¸è‡ªæ®º! è«‹è€ƒæ…®ç¶œæ´ (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

 

[Man-wai Chang]

A series of unfortunate events. It seems that the real problem was my
ISP. Possibly it started limiting my bandwidth on the same day I
discovered that loosen LAN plug.

--
@~@ You have the right to remain silence.
/ v \ Simplicity is Beauty! May the Force and farces be with you!
/( _ )\ (x86_64 Ubuntu 9.10) Linux 2.6.39.1
^ ^ 22:44:01 up 1 day 6:53 0 users load average: 1.21 1.11 1.06
ä¸å€Ÿè²¸! ä¸è©é¨™! ä¸æ´äº¤! ä¸æ‰“交! ä¸æ‰“劫! ä¸è‡ªæ®º! è«‹è€ƒæ…®ç¶œæ´ (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

 

[Man-wai Chang]

A series of unfortunate events. It seems that the real problem was my
ISP. Possibly it started limiting my bandwidth on the same day I
discovered that loosen LAN plug.

And it seems that the problem is limited to my ISP's DNS servers only.

Sorry for being mis-directed by that loosen LAN plug.

--
@~@ You have the right to remain silence.
/ v \ Simplicity is Beauty! May the Force and farces be with you!
/( _ )\ (x86_64 Ubuntu 9.10) Linux 2.6.39.1
^ ^ 00:54:01 up 1 day 9:03 0 users load average: 1.08 1.08 1.09
ä¸å€Ÿè²¸! ä¸è©é¨™! ä¸æ´äº¤! ä¸æ‰“交! ä¸æ‰“劫! ä¸è‡ªæ®º! è«‹è€ƒæ…®ç¶œæ´ (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

 

[Man-wai Chang]

And it seems that the problem is limited to my ISP's DNS servers only.

Sorry for being mis-directed by that loosen LAN plug.

Adding Google's public DNS server 8.8.8.8 to the router.

--
@~@ You have the right to remain silence.
/ v \ Simplicity is Beauty! May the Force and farces be with you!
/( _ )\ (x86_64 Ubuntu 9.10) Linux 2.6.39.1
^ ^ 01:09:02 up 1 day 9:18 0 users load average: 1.00 1.03 1.05
ä¸å€Ÿè²¸! ä¸è©é¨™! ä¸æ´äº¤! ä¸æ‰“交! ä¸æ‰“劫! ä¸è‡ªæ®º! è«‹è€ƒæ…®ç¶œæ´ (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

 

[Paul]

Is there someplace where I can find out the speeds of different
routers (actual router speed, not LAN or WAN interface speed)?

This is the closest I know of, to a site that compares products.
Does their "Total Simultaneous Throughput" measurement, measure
something useful ? Not sure.

http://www.smallnetbuilder.com/lanwan/router-charts/view

Paul