Network Switch not working except one with uplink

[al1988]

Hi I have a weird problem. I am tech and serving a customers CCTV system. This is an exiting system that was working.
We have a parking lot, 1 main box with a 16-port switch that is connected to main campus LAN. I have about 8 cameras 3 is connected directly to the main switch is working fine.

For some reason the original installation two switches was installed underground to link all the other cameras.

1. 1 cable from main switch (SM1) to 1 switch - connected to 3 CAMS

2. output of the first switch (SM1) is connected to a second switch let call it SM2.

Both old SM1 and SM2 has uplink port.

for some reason both SM1 and SM2 went bad.

So i replaced SM1 with a regular switch (no separate up link ) and it will not connect to the main switch. NO connection to facility LAN. The activity light doesn't come on.
I am using separate cable to power the switch. 12V. I check and I know it not a power issue.

a. if i connect the new SM1 directly to main switch, it works. using a patch cable.
b. if I connect my laptop directly to the feed where SM1 is installed, it works. So I know my cable and connection is good.
c. I connected a wireless router and that works. The router has a up link. Its a wireless router I use for my internet connection at home. I use it to troubleshoot in the field.

My feed from main SW to SM1 is straight thought B - Existing. from my research, an up link is a cross over. I tested the new SW adding a cross over cable and still won't work at the remote location. I cannot get an answer even from the facility's network techs. I am not a network guy, I am electronics tech but broad field in security, electronics and controls.
This one has baffles me.
If anyone have any idea why is this please give me your opinions.

Thanks a lot

Al

 

[bill001g]

So you get a connection light but you think there is no traffic? If these are managed switches can you see the port status like link speed.

The concept of crossover cables is not really valid anymore. Almost all switches even 100m ones have mdi/mdix feature to negotiate this. On gig ports there is no such thing as a cross over it transmits and receives on all 4 pair on both ends at the same time. If you use cross cable on gig ports it will at times get confused and drop to 100m.

I am surprised you did not have a big problem when you had both switch connected to the main switch as well as directly connected together. That causes a loop in the network. Your switches may have spanning tree on and they may have blocked one of the connections.

There is not a lot that can block traffic on a switch when the port is actually active. Maybe port security limiting the mac addresses allowed. Spanning tree would be a concern if you had multiple vlans, you can get some vlans blocked on different cables. Still if there is only a single path spanning tree will not block anything.

 

[al1988]

So you get a connection light but you think there is no traffic? If these are managed switches can you see the port status like link speed.

The concept of crossover cables is not really valid anymore. Almost all switches even 100m ones have mdi/mdix feature to negotiate this. On gig ports there is no such thing as a cross over it transmits and receives on all 4 pair on both ends at the same time. If you use cross cable on gig ports it will at times get confused and drop to 100m.

I am surprised you did not have a big problem when you had both switch connected to the main switch as well as directly connected together. That causes a loop in the network. Your switches may have spanning tree on and they may have blocked one of the connections.

There is not a lot that can block traffic on a switch when the port is actually active. Maybe port security limiting the mac addresses allowed. Spanning tree would be a concern if you had multiple vlans, you can get some vlans blocked on different cables. Still if there is only a single path spanning tree will not block anything.

Thanks.
I will investigate more and if I find a solution, will post back.