Please Help Me Troubleshoot My Cisco Catalyst 2848G

[Party1]

I bought a 2948G switch from eBay few months back and have not been able to get it to work: e.g. getting it to work as a switch. I read through the 400 page manual and was able to reset it to factory defaults. I did not find any information on the configuration needed to provide "basic switching" thus am assuming that it should work out of the box (restored factory settings). It is running through self tests OK. It is unable to provide network access to any computers/network devices attached to it. I do not know if this is a defective switch or my incompetence.

Here is my current configuration:

DSL_Modem (192.168.0.1)--->Router_Main (192.168.42.1)--->Switch_1--->Switch_3--->Switch_4

This is what I am hoping to achieve:

DSL_Modem (192.168.0.1)--->Router_Main (192.168.42.1)--->Switch_1--->Switch_4--->Switch_3


Neither configuration works at this moment. Please help me troubleshoot the issue.

Thank you!

=)



DSL_Modem (192.168.0.1) = Seeman's Speedstream 4100

Router_Main (192.168.42.1) = PC running M0n0Wall software with one WAN(DSL modem) interface & one LAN(Switch_1) interface

Switch_1 = 5 port Netgear Switch 10MB:
[S1_int1] - Network Server(192.168.42.2)
[S1_int2] - HTPC(192.168.42.253)
[S1_int3] - Switch_2 (192.168.42.3)
[S1_int4] - Switch_3 (192.168.42.4)

Switch_2 = Linksys WRT54GS router switch (192.168.42.3) acting as a switch
[S2_int1] - WAN (unused)
[S2_int2] - PC1 via Router_Main DNS (192.168.42.x)
[S2_int3] - PC2 via Router_Main DNS (192.168.42.x)
[S2_int4] - PC3 via Router_Main DNS (192.168.42.x)
[S2_int4] - PC4 via Router_Main DNS (192.168.42.x)


Switch_3 = Linksys WRT150N router switch (192.168.42.3) acting as a switch
[S3_int1] - WAN (unused)
[S3_int2] - PC1 via Router_Main DNS (192.168.42.x)
[S3_int3] - PC2 via Router_Main DNS (192.168.42.x)
[S3_int4] - PC3 via Router_Main DNS (192.168.42.x)
[S3_int4] - Switch_4

Switch_4 = Cisco Catalyst 2948G reset to factory defaults with latest CATOS
[S4_int1] = PC5 (UNABLE TO ACHIEVE A VALID NETWORK ADDRESS)

 

[vipergg]

Ubplug your other switches then plug the 2948G right to the router . If you actuyally factory defaulted the switch with a "clear config all" command it should work right out of the box except do the following thing first before plugging anything in.

If you are trying dhcp thru the 2948G then for all user ports use the "set port host" command for all the ports , to turn it on for all ports use "set port host 2/1-48" . This turns on portfast and turns off trunking and channeling to bring the user port up immediately instead of waiting for spanning tree to run which takes 40-50 seconds and will time out a dhcp request from a user devie.

 

[Party1]

Hi vipergg!

By following the advice of a very nice member of networking-forums.com I disabled STP ("set spantree portfast 2/1-48 enable"), but I am not sure if it did much (I will leave it off anyway).
I also decided to go ahead and setup the network in this manner:

<b>[FIGURE_B]</b>

<b>
DSL_Modem</b> (192.168.0.1)---><b>Router_Main</b> (192.168.42.1)---><b>Switch_1</b>x===x<b>Switch_4</b>x===x<b>Switch_3</b>

Unfortunately it does not work (I can not get through to the internet from Switch_4).

The network still works (Switch_4's PCs have access to the internet) in the old configuration:

<b>[FIGURE_A]</b>
&#9;
<b>
DSL_Modem</b> (192.168.0.1)---><b>Router_Main</b> (192.168.42.1)---><b>Switch_1</b>x===x<b>Switch_3</b>x===x<b>Switch_4</b>

To alleviate any further complications I took up another suggestion of the aforementioned poster and ran crossover cables between: Switch_1 & Switch_3; Switch_3 & Switch 4. Mainly I did this to avoid these particular Layer 1 suspicions.

Now my main point of concern is removing the Switch_3 as a middle man between Switch_1 & Switch_4 and add it to Switch_4 as a wireless access point (just like Switch_2 is off Switch_1).

Unfortunately this preferred configuration (FIGURE_B) does not currently work for what ever reason.

How would you suggest I go about troubleshooting this issue?

I ran "set port host 2/1-48" as well - thanks for that!

P.S. Thank you for posting the reply in the other forum as well - that was really nice!

=)

 

[Party1]

I apologize for being unclear:

The problem seems to originate (please refer to FIGURE_B) between Switch_1 & Switch_4.

Switch_4 (2948g) does indeed see Switch_3 when it is connected to it, but it does not see Switch_1 when it is connected directly to it.

As switch one is on the way to my gateway, I am unable to get on the internet.

The only way Switch_4 gets internet from Switch_1 is if Switch_3 is connected between them: internet....Switch_1x===xSwitch_3x===xSwitch_4

 

[Party1]

I made a crucial mistake: I mistakenly made a straight-through cable instead of the crossover cable between Switch_1 & Switch_4

 

[Party1]

SOLVED:

SOLVED!

[FIGURE_B]

DSL_Modem (192.168.0.1)--->Router_Main (192.168.42.1)--->Switch_1--->Switch_4--->Switch_3

To summarize:

I have used the following methods to achieve a working topology (FIGURE_B) as diagrammed above:

[1] I replaced all cables between switches from straight-through cables to crossover cables.

[2] I typed following commands from enable mode of my Cisco Catalyst 2948g:

set spantree portfast 2/1-48 enable
set port host 2/1-48

Thank you very much for your most excellent help vipergg!!!!

 

[vipergg]

That means switch does not use mdix to auto correct the cable polarity while your other switch 3 probably does and why a straight thru worked between those 2 .

 

[vipergg]

Also I would also check to make sure you put your link port back to auto , more than likely the netgear is auto only and this would give you a duplex mismatch if you left it as 10/full on the 2948.

 

[Party1]

Thanks again!
Bink from the other forum gave me a heads up about port mismatch right around the same time that I noticed that my speeds dropped to 1/6 of my previous connection.


I ran:

clear config all
set spantree portfast 2/1-48 enable
set port host 2/1-48

and my speeds are as good as they were with Linksys.


I am getting 8MB/s to my server (on Switch_1)- does that seem to be about right for my configuration?


P.S. set spantree portfast 2/1-48 enable (Do I need this comman at all? Is it helping anything? Seems like set port host 2/1-48 does it all for me...)


P.S.S. By the way, I mistakenly called Switch_1 a Netgear 10Mb - it actually is a D-Link DES-3205 Flex Switch

 

[vipergg]

No set port host includes the spanning tree portfast command , it is a command that does 3 things in one command. 8 Mb's is about right probably as it is a 100 megabit port so 8 bits to a bytes plus overhead its probably pretty close I would think .

 

[Party1]

Sounds like it is perfect now!


SOLVED with Vipergg's help!


[FIGURE_B]

DSL_Modem (192.168.0.1)--->Router_Main (192.168.42.1)--->Switch_1--->Switch_4--->Switch_3


To summarize:

I have used the following methods to achieve a working topology (FIGURE_B) as diagrammed above:

[1] I replaced all cables between switches from straight-through cables to crossover cables.

[2] I typed following commands from enable mode of my Cisco Catalyst 2948g:

clear config all
set port host 2/1-48

 

[burtsbees]

So give viper a star!

Burt