Switch 2920-48G-POE+ (J9729A)

[adelgado]

Hi,

I've just bough two 2920-48G-PoE switches, with four (two per Switch) transceivers HP X121 (J4858C), that the matrxi says is ok.

We've also installed fiber topolgy between our offices and our plant.

The issue that I'm facing now is that when I connect both fiber cables from switch to switch, I loose connectivity.  I'm connecting them from port 45 to port 45 and from port 47 to port 47. I've also tried exchanging ports.

I got "Excesscive broadcasts detected on port 45" and the same for port 47  on alert log.

What am I doing wrong?

PD: there is no VLAN creates nor stacking active, although one of the switches has installed the stacking module. Also, both swtiches has the last firmware.

Regards,

[adelgado]

Sorry, I forgot to say that with one fiber cable is fine, there is connectivity.

[HP-Browniee]

Hi

If you connect 2 fibers from 1 switch to another in the same vlan, you have to make a trunk link, to bundle those links, else you will make a loop.

Try to do following command on both switches:

trunk 45,47 trk1 lacp

Kind regards

[adelgado]

Oh my God!!!

I've tested , and voilà!!!

Well, and if I have more than one VLAN, how should I configure those ports to be in trunk mode? I would like to implement policies, so that VLAN1 hosts not able to access VLAN2, VLAN3 members access to VLAN2, etc. I have other swtiches as well, like 2510, 2530, 2848 and 1800. Should I connect those swtiches to 2920 switches, wich will be the core ones?

I'm planning that hosts on production area (VLAN1), not be able to access hosts on office (VLAN2), but able to access servers (VLAN3), hosts on office (VLAN2) be able to access servers (VLAN3), but not production area hosts (VLAN1), etc.

Thanks a lot,

[HP-Browniee]

Hi

If you want more vlans over a trunk link you should tag them.

For example:

vlan 1
untagged trk1
vlan 2
tagged trk1
vlan 3
tagged trk1

I have no idea, how your network setup is. so it is hard to tell what you  are using as core. Normally the core switches are the switches were routing is enabled.

+++ If these postes were usfull give it a kudo and mark it as solved : ) +++

[adelgado]

I see, don't worry.

BTW, one question. Now that I have those two switches working, how could I connec them to the ones I already have? None of the existent ones have VLAN configure, but trunking is enable on some of them for redundancy link between them.

Imagine I have two 2530 connected between them with a trunk, this is, with two CAT5 cables. How could I integrate the 2920 to this structure? Having into account I'd like to be redundant, I understand I could connect one of the 2920 to one of the 2530, and the other 2920 to the other 2530. Do you agree? Should I perform any other steps?

Thanks a lot

[HP-Browniee · Accepted solution]

Hi

If you want to be redundant you will have to use spanning-tree. Unless you have some stacked switches.

It should be somthing like this:

If you connect your 2920 switches to switches with only 1 vlan(the default vlan), you just have to connect them in vlan 1. So you will be fine when you just untag the ports in vlan 1 between those switches.

for example: 

vlan 1
untagged 40

If spanning-tree is enabled, it will always block 1 port on each switch to prevent a loop.

+++ If these postes were usfull give it a kudo and mark it as solved : ) +++

[adelgado]

I will stack the 2920, as I have the cables and module. But that will be done on the following weeks, not right now. I was triying to know how to add those switches to the structure I already have.

Thanks a lot,