Help on a connection to a Cisco 2970G

TType85

[H]ard|Gawd
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I am having some issues putting a Cisco 2970G in place of a HP Procurve that we need to return (leased hardware). I am not really a networking guy, I know just enough to get around and in to stuff.

On the Procurve our internet connection (Mosaic 100MB line) comes in to one of the SFP ports, I have PFSense as our router/firewall. When we moved the switch there we plugged it in and it worked without any issue.

I put one of our spare 2970G switches in, connected everything up and all the RJ-45 ports work without issue. I plug a cisco SFP adapter in and plug the mosaic line in and nothing. The switch shows that there is a SFP adapter plugged in to the port (tried all 4) but no connection. I know on the connection info from Mosaic they specify it MUST be set up as 1000MB Full Duplex. The web GUI on the 2970 won't let me change it on a port that is not up.

Is there a way to set it to 1000MB Full Duplex before I plug it in? I can telenet in to it if needed.

Right now to keep the connection up I have the Mosaic line going to the HP Switch, the PFSense WAN plugged in to that switch and the LAN side plugged in to the 2790G.

Also, how can I set up a VLAN with just the SFP port and one other port to make sure the traffic from the WAN is separated from LAN traffic on the switch?
 

thrash408

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The SFP is always 1000MB Full Duplex, you can't change those to 100MB i'm pretty sure.
 

TType85

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The SFP is always 1000MB Full Duplex, you can't change those to 100MB i'm pretty sure.

I just wonder why it's not coming up. I connected the switch to another switch via the SFP ports and it was fine, both came up, 1000MB.
 

green91

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You need to read the log on the switch. Cisco are very particular about what gbics they will accept. If it doesn't like the transceiver, it will show in the log.

You can still force the duplex/speed (1000/f) or set it to auto, even on a SFP.

Also, quit using the GUI :)
 

thrash408

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Yeah, i've seen a cisco switch throw errors via the CLI because i was trying to use a Dell gbic. if you console on it should show any errors
 

TType85

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You need to read the log on the switch. Cisco are very particular about what gbics they will accept. If it doesn't like the transceiver, it will show in the log.

You can still force the duplex/speed (1000/f) or set it to auto, even on a SFP.

Also, quit using the GUI :)

Learning the CLI. the adapters work fine doing a switch to switch connection.
 

mikey71497

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What type of SFP? 1310 single mode or 850 multi? Do you have a optical power meter where you can take a power measurement coming out of each optic o make sure you have light in both directions? Are the optical ports a combo with the RJ45? If so you may have to change he media type On The physical interface to SFP

Sounds like a speed/duplex problem though. Set the Cisco side to auto see if the port comes up.
 
Last edited:

green91

Limp Gawd
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If the same GBIC works in the same switch to another switch, the next step i'd try is duplex/speed.

>en
#conf t
(config)# int gi0/24 (or whatever the int is)
(config-if)# speed auto
(config-if)# duplex auto

likewise if you need to force it (ive never seen you NEED to force a SFP)
(config-if)# speed 1000
(config-if)# duplex full
 

TType85

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What type of SFP? 1310 single mode or 850 multi? Do you have a optical power meter where you can take a power measurement coming out of each optic o make sure you have light in both directions? Are the optical ports a combo with the RJ45? If so you may have to change he media type On The physical interface to SFP

Sounds like a speed/duplex problem though. Set the Cisco side to auto see if the port comes up.

Unfortunately no real network tools. This one has the 4 SFP marked as 25-28, just to be safe, nothing is on 21-24.
 

TType85

[H]ard|Gawd
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If the same GBIC works in the same switch to another switch, the next step i'd try is duplex/speed.

>en
#conf t
(config)# int gi0/24 (or whatever the int is)
(config-if)# speed auto
(config-if)# duplex auto

likewise if you need to force it (ive never seen you NEED to force a SFP)
(config-if)# speed 1000
(config-if)# duplex full

Will give that a try tomorrow.
 

green91

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If the connector has been split, you may also need to try swapping the pairs.
 

Blue Fox

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Gotta throw this out there just in case. :p

Code:
>en
#config t
(config)# int gi0/25
(config-if)# no shut

As for your VLANs:

Code:
>en
#config t
(config)# int gi0/25
(config-if)# switchport access vlan [2-4095]
 

just2cool

Gawd
Joined
Sep 22, 2005
Messages
524
en
conf t
int g0/25
speed nonnegotiate

This is 100% likely to solve your problem, provided it is a working Cisco SFP supported by the 2970 and the fiber isn't damaged. Those speed 1000 / duplex commands don't apply for this. And flip polarity again if you have to.

This is the most overlooked command when dealing with Cisco, SFPs, and other gear. I have used it countless times, yet despise cisco for implementing it this way. So many people have wasted so much time in the past troubleshooting link issues because of this, much like you are now.

Per Cisco's site:
"You cannot configure speed on most SFP module ports, but you can configure the speed not to negotiate (speed nonegotiate) if the port is connected to a device that does not support autonegotiation."
 

Electrofreak

[H]ard|Gawd
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en
conf t
int g0/25
speed nonnegotiate

This is 100% likely to solve your problem, provided it is a working Cisco SFP supported by the 2970 and the fiber isn't damaged. Those speed 1000 / duplex commands don't apply for this. And flip polarity again if you have to.

This is the most overlooked command when dealing with Cisco, SFPs, and other gear. I have used it countless times, yet despise cisco for implementing it this way. So many people have wasted so much time in the past troubleshooting link issues because of this, much like you are now.

Per Cisco's site:
"You cannot configure speed on most SFP module ports, but you can configure the speed not to negotiate (speed nonegotiate) if the port is connected to a device that does not support autonegotiation."

Heh, I'd completely forgotten about speed nonegotiate. It's one of those commands you learn about the hard way.
 

Electrofreak

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jumbo frame config.. issue

Dude, the problem has already been resolved, and it had nothing to do with jumbo frames.

This is the third thread where I've replied to an absolutely ridiculous recommendation on your part that demonstrates a complete lack of understanding of either the problem or the technology you're recommending as the solution, I'm not sure which.
 

TType85

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Messages
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This isn't solved yet :(. I was able to get to the datacenter today and tried the commands with no change.

I hooked the console cable up to the hp switch and the vlan has a IP address (4.53.xx.xx) the port the mosaic connection is going is set to 1000 full duplex and works perfect.

I plug the connection to the hp switch and it does not come up. I plug a connection between the Cisco switch and another using the sfp port it comes up fine. 2790g plugged into a 3750g.

Can I set the ip/subnet on the Cisco switch? I connect the hp to the Cisco and the hp lights up but the Cisco didn't.

I wish we had our network guy still :/
 

Blue Fox

[H]F Junkie
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Jun 9, 2004
Messages
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Yes, you can set the address.

Code:
>en
#config t
(config)# ip default gateway [address]
(config)# int vlan1
(config-if)# ip address [address] [netmask]
 

tangoseal

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Dec 18, 2010
Messages
9,330
Ttype.... so your problem is that the SFP will not "turn on" ..

Are you using genuine Cisco SFPs? If not use the following command line:

service unsupported-transceiver

Also do a "show interface (interface name) capabilities" and you should see the following (real output from my 3750e):

Switch#sh interfaces tenGigabitEthernet 1/0/1 capabilities
TenGigabitEthernet1/0/1
Model: WS-C3750E-24TD
Type: 10GBase-SR
Speed: 10000
Duplex: full
Trunk encap. type: 802.1Q,ISL
Trunk mode: on,off,desirable,nonegotiate
Channel: yes
Broadcast suppression: percentage(0-100)
Flowcontrol: rx-(off,on,desired),tx-(none)
Fast Start: yes
QoS scheduling: rx-(not configurable on per port basis),
tx-(4q3t) (3t: Two configurable values and one fixed.)
CoS rewrite: yes
ToS rewrite: yes
UDLD: yes
Inline power: no
SPAN: source/destination
PortSecure: yes
Dot1x: yes
Switch#

Are you able to visibly see a laser shooting out of the fiber hooked into the Cisco SFP? Use your cellphone camera to safely look at the fiber tip and you will see a bright glow on your screen or if you are ballsy like me just look at the shit with your naked eye and see if there is a laser coming out.

What exact model of SFP are trying to use and we can start some troubleshooting commands to help you.

Also does this switch have a TAC warranty agreement and if so why in the hell are you on this forum LOL let Cisco's amazing tech support assist you.
 

tangoseal

[H]F Junkie
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Messages
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Oh crap I went back and took a look at your post TTYPE...

Do me a favor and look up the model number of the HP Transceiver and look up the model of the Cisco transceiver.

I am almost betting you that you have mismatched incompatible hardware here....

i.e. One is shortreach and the other is longreach or one is Laser (Cisco's use almost all lasers) and HP might be using LED. The problem is that the optics on laser based transceiver are tuned to only receive laser light and LEDs only to receive LED light waves.There are convertors out there and you may need one.

Also are you using multimode fiber or singlemode fiber, if you are using singlemode optics on MM fiber you need to use a Mode Conditioning Patch Cord.

What we appear to be having here is a layer 1 issue. There is something wrong with the physical networking layer and we need to process troubleshooting against that layer first before we can move on to the 2nd layer (data-link i.e. switching)
 

green91

Limp Gawd
Joined
Sep 2, 2012
Messages
398
^^ this is good advice,

You can also loop a single jumper back to the gbic to see if the link light comes up. Don't leave it plugged in very long like this, I've only done this in extreme diagnostic situations :)
 

TType85

[H]ard|Gawd
Joined
Jul 8, 2001
Messages
1,487
Ttype.... so your problem is that the SFP will not "turn on" ..

Are you using genuine Cisco SFPs? If not use the following command line:

service unsupported-transceiver

Also do a "show interface (interface name) capabilities" and you should see the following (real output from my 3750e):

Switch#sh interfaces tenGigabitEthernet 1/0/1 capabilities
TenGigabitEthernet1/0/1
Model: WS-C3750E-24TD
Type: 10GBase-SR
Speed: 10000
Duplex: full
Trunk encap. type: 802.1Q,ISL
Trunk mode: on,off,desirable,nonegotiate
Channel: yes
Broadcast suppression: percentage(0-100)
Flowcontrol: rx-(off,on,desired),tx-(none)
Fast Start: yes
QoS scheduling: rx-(not configurable on per port basis),
tx-(4q3t) (3t: Two configurable values and one fixed.)
CoS rewrite: yes
ToS rewrite: yes
UDLD: yes
Inline power: no
SPAN: source/destination
PortSecure: yes
Dot1x: yes
Switch#

Are you able to visibly see a laser shooting out of the fiber hooked into the Cisco SFP? Use your cellphone camera to safely look at the fiber tip and you will see a bright glow on your screen or if you are ballsy like me just look at the shit with your naked eye and see if there is a laser coming out.

What exact model of SFP are trying to use and we can start some troubleshooting commands to help you.

Also does this switch have a TAC warranty agreement and if so why in the hell are you on this forum LOL let Cisco's amazing tech support assist you.

From the switch:
GigabitEthernet1/0/25
Model: WS-C3750G-24TS-1U
Type: 1000BaseSX SFP
Speed: 1000
Duplex: full
Trunk encap. type: 802.1Q,ISL
Trunk mode: on,off,desirable,nonegotiate
Channel: yes
Broadcast suppression: percentage(0-100)
Flowcontrol: rx-(off,on,desired),tx-(none)
Fast Start: yes
QoS scheduling: rx-(not configurable on per port basis),tx-(4q2t)
CoS rewrite: yes
ToS rewrite: yes
UDLD: yes
Inline power: no
SPAN: source/destination
PortSecure: yes
Dot1x: yes

The SFP is a GLC-SX-MM.

If i loop from one SFP port on the switch to the other (port to port, same switch) port 25 comes up.

As for the warranty. Most likely not. We have had the switches since 2006 and I know there has been no support money paid for at least 3 years.
 

TType85

[H]ard|Gawd
Joined
Jul 8, 2001
Messages
1,487
Oh crap I went back and took a look at your post TTYPE...

Do me a favor and look up the model number of the HP Transceiver and look up the model of the Cisco transceiver.

I am almost betting you that you have mismatched incompatible hardware here....

i.e. One is shortreach and the other is longreach or one is Laser (Cisco's use almost all lasers) and HP might be using LED. The problem is that the optics on laser based transceiver are tuned to only receive laser light and LEDs only to receive LED light waves.There are convertors out there and you may need one.

Also are you using multimode fiber or singlemode fiber, if you are using singlemode optics on MM fiber you need to use a Mode Conditioning Patch Cord.

What we appear to be having here is a layer 1 issue. There is something wrong with the physical networking layer and we need to process troubleshooting against that layer first before we can move on to the 2nd layer (data-link i.e. switching)

I don't have the SFP of the HP switch with me but it really does not need to link the two switches together, I was just trying to test the ports that way. I can see the laser on the Cisco.

I don't know what a MM fiber is, but the drop into the rack is a SC connection, we have a SC to SFP cord connecting it to the switch. Whatever we have works right with the HP but not the Cisco AUGH!
 

tangoseal

[H]F Junkie
Joined
Dec 18, 2010
Messages
9,330
I don't have the SFP of the HP switch with me but it really does not need to link the two switches together, I was just trying to test the ports that way. I can see the laser on the Cisco.

I don't know what a MM fiber is, but the drop into the rack is a SC connection, we have a SC to SFP cord connecting it to the switch. Whatever we have works right with the HP but not the Cisco AUGH!

Yeah you have a hardware technology mismatch more than likely.

As far as your Cisco SFP it is using an 850nm Laser and it can only connect to other SFPs that use 802.3z ethernet standard. You will have to share with me the model of the HP transceiver once you get the chance and if the HP is a different technology then we have found your problem. Now what you can do is see if HP will support NON HP brand SFP with a special command line and take one of your extra Cisco SFPs and stuff it in the HP switch and see if it works. But check to make sure that the HP uses industry standard SFP spec devices i.e. voltages etc... I am almost 100% there is documentation out there.

I unfortunately only know Cisco and a little Juniper but NOTHING Hewlett Packard at all :-(
 

TType85

[H]ard|Gawd
Joined
Jul 8, 2001
Messages
1,487
Yeah you have a hardware technology mismatch more than likely.

As far as your Cisco SFP it is using an 850nm Laser and it can only connect to other SFPs that use 802.3z ethernet standard. You will have to share with me the model of the HP transceiver once you get the chance and if the HP is a different technology then we have found your problem. Now what you can do is see if HP will support NON HP brand SFP with a special command line and take one of your extra Cisco SFPs and stuff it in the HP switch and see if it works. But check to make sure that the HP uses industry standard SFP spec devices i.e. voltages etc... I am almost 100% there is documentation out there.

I unfortunately only know Cisco and a little Juniper but NOTHING Hewlett Packard at all :-(

Thank you for the help. The point is going to be getting rid of the HP switch (it is leased). We have the connection that comes in to the colo from Mosaic (our provider) and is run as a fiber connection down to the rack. It is a SC connection, there is a SC to SFP adapter cord between there and the HP switch. I want to plug it in to the Cisco switch instead, but when it is hooked up there is no connection. I know the ports are functional and the SFP adapter works when connected to another cisco switch.
 

mattjw916

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Messages
1,289
I can see the laser on the Cisco
I hope you didn't point that into your eye lol... The short range stuff probably won't hurt you (much) but the long-range stuff could probably blind you if you were using the wrong transceiver.
 

TType85

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Messages
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I hope you didn't point that into your eye lol... The short range stuff probably won't hurt you (much) but the long-range stuff could probably blind you if you were using the wrong transceiver.

Lol, no I used my phone :p
 

just2cool

Gawd
Joined
Sep 22, 2005
Messages
524
A bit more of a stretch, try "switchport nonnegotiate" as well. I recall this giving me problems at some point. This "feature" is called DTP and tries to negotiate the other side to be a trunk and occasionally confuses the other side. (another annoying Cisco command btw).

Also, try playing around with UDLD (another Cisco proprietary protocol). Don't get excited if you see link up right away -- the other side might still be link down. Underneath the fiber interface, try "udld port disable".

Third, use your phone again, and make sure polarity lines up (each laser should be on its separate glass)

Finally, make your provider help. There are two sides to every link. I setup well over 200 different external vendor links ranging from copper, single mode, multimode (50 micron and 62.5 micron ... big problem at 10gig+), media converters that I found with a surprise ... and speeds ranging from 1.544 Mbps to 40 Gbps. Sometimes they need to do something in order to get it to work with my gear or vice-versa. If they are unwilling to help, then tell them you're getting another provider because their service is currently useless to you.

Here are the questions I would start with:
- Are you connecting to a switch or a router?
- What is their device model?
- What is their transceiver type/model?
- Do they have UDLD enabled or something similar?
- Do they have any proprietary stuff enabled?
- How are their speed settings set?
- How is their port configured, L2 or L3? (if L2, then what is their spanning tree mode?)
- Do they see link up but you don't? (This really happens a lot with fiber)
- What type of fiber are they using from them to you? (50 micron MM, 62.5 micron MM, 7 micron SM)
- What is the distance to the demarc from your location?
- What happens when they put a loop cable up on their side? Do you get link up?
- What happens when you put up a loop cable on your side? Do they get link up?
- Can they come out and use a tool to measure Rx light levels at both devices?
- Tell them to mess around with speed settings, and if you both get link up, tell them their standard won't work since you've tried everything on your side, and force them to leave it that way.

And since you asked about fiber:
7 micron SM fiber is generally a yellow cable
50 micron MM is generally an aqua blue cable (though can occasionally be a thin orange cable)
62.5 micron MM is generally a thick orange cable

Never mismatch these through the entire link, even 50 MM with 62.5 MM.
 
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