Cisco SG200-08 is dropping IP fragments

C

Captain Kirk

Limp Gawd
Joined
Dec 22, 2002
Messages
288
MTU on my switch ports is at 1518 (the default). I had noticed that my PlayStation and a few games complained about problems with IP fragments, so I decided to test things out a bit. Sure enough, fragments were getting dropped. A ping like this:
Code: 
$ ping -s 1472 192.168.1.x
would go through, but one like this:
Code: 
$ ping -s 1473 192.168.1.x
wouldn't make it. I swapped in another switch and it worked fine. Sadly, that switch has less ports than the SG200. It seems I'm not the only one with this issue. The unit is well out of warranty, so my current hack job is to tie in the unaffected switch and connect the hosts that are having this difficulty through it.

Anyone have any ideas on resolving this?
 
Have you tried disabling all kinds of "overload"/DoS-protections (if any)?
//Danne
 
diizzy said:
Have you tried disabling all kinds of "overload"/DoS-protections (if any)?
//Danne
Click to expand...
I saw mention of that on Cisco's website, but I don't think it applies to this particular model. I couldn't find DoS-type settings anywhere.
 
You're probably out of luck on unfortunately in that case :-(
//Danne
 
diizzy said:
You're probably out of luck on unfortunately in that case :-(
//Danne
Click to expand...
That's unfortunate. I currently have the hosts that are picky about fragments on a separate, older gigabit switch that's also hooked into the Cisco.

I'm thinking I shouldn't see much of a performance hit from an older gigabit switch, assuming my link is still 1000 - right? The only downside is the switch is unmanaged (no stats, etc.).
 
Same issue here. I commented in the issue thread as I actually have gotten one annoying subtle network breakage bug fixed that way for SB200-08 already.
 
marsboer said:
Same issue here. I commented in the issue thread as I actually have gotten one annoying subtle network breakage bug fixed that way for SB200-08 already.
Click to expand...
A bit of an update on this. I actually ended up convincing Cisco Small Business Support to open a case with the TAC for me. Apparently, this switch's bad behavior is a "design feature." It doesn't support jumbos either, which is why some of my other non-fragmented tests were failing too. Why this isn't documented (well) is beyond me. I was told to upgrade to a SG300 series, which doesn't have these features :rolleyes:. Asked if I could do the trade-up or upgrade to the 300 series and was told that I'd need to pay retail for the 300, despite the 200 not living up to its expectations.

I instead swapped out the SG200 for a TP-Link TL-SG3216. The price was on par with what I originally paid for the Cisco. This switch has twice the ports (16) and has a very similar IOS type interface. After rewiring everything, I was happy to notice that I wasn't seeing anymore packet loss on any of my interfaces. PSN is happy and a few of my other networks apps that would occasionally misbehave all the sudden started playing nice. What do you know ;)?

Not quite sure how I feel about Cisco products anymore, though...
 
Captain Kirk said:
A bit of an update on this. I actually ended up convincing Cisco Small Business Support to open a case with the TAC for me. Apparently, this switch's bad behavior is a "design feature." It doesn't support jumbos either, which is why some of my other non-fragmented tests were failing too. Why this isn't documented (well) is beyond me. I was told to upgrade to a SG300 series, which doesn't have these features :rolleyes:. Asked if I could do the trade-up or upgrade to the 300 series and was told that I'd need to pay retail for the 300, despite the 200 not living up to its expectations.

I instead swapped out the SG200 for a TP-Link TL-SG3216. The price was on par with what I originally paid for the Cisco. This switch has twice the ports (16) and has a very similar IOS type interface. After rewiring everything, I was happy to notice that I wasn't seeing anymore packet loss on any of my interfaces. PSN is happy and a few of my other networks apps that would occasionally misbehave all the sudden started playing nice. What do you know ;)?

Not quite sure how I feel about Cisco products anymore, though...
Click to expand...

You can't judge real Cisco products by their shitty Linksys rebadges and SMB stuff. Their enterprise lines are great.
 
Bummer, you could've picked up a Zyxel GS1910 for the same price which is much better than the TP-Link btw...
//Danne
 
A so-called "telco class" switch by Zyxel blew up in my face[1] because of leaking capacitors after only 4 years...

What can you actually buy these days?

[1] not literally
 
Raw performance is noticable better...
* Faster backend, 32 vs 48Gbit
* Packet Forwarding Rate, 23.8 vs 35.7Mpps

I prefer Zyxels WebUI over TP-Links as it seems a bit more organized but that's a personal preference and there seems to be smaller differences here and there but not that much. I do however when it comes to switches rate Zyxel much higher the TP-Link.
//Danne
 
diizzy said:
Raw performance is noticable better...
* Faster backend, 32 vs 48Gbit
* Packet Forwarding Rate, 23.8 vs 35.7Mpps

I prefer Zyxels WebUI over TP-Links as it seems a bit more organized but that's a personal preference and there seems to be smaller differences here and there but not that much. I do however when it comes to switches rate Zyxel much higher the TP-Link.
Click to expand...
So 48 makes sense for the Zyxel since it's a 24-port vs. a 16. Not sure I'll scratch that PPS rate in my usage scenarios. Do you push that much traffic?
 
No I don't, but I do try to get the most bang for the buck ;-)

Should be mentioned that TP-Link gives you 5 years warranty compared to Zyxels 2 year.
//Danne
 
diizzy said:
No I don't, but I do try to get the most bang for the buck ;-)

Should be mentioned that TP-Link gives you 5 years warranty compared to Zyxels 2 year.
Click to expand...
I'll give you bang for your buck. I got the TP-Link on sale at a pretty solid discount.

I just did the math and that 23.8 number comes from maxing out 16 GE ports. Makes sense, I think.
 
Unless you use the 10Gbe ports...

Anyhow, I just compared the retail prices which is without 10$ apart... (around 180$)
//Danne
 
diizzy said:
Unless you use the 10Gbe ports...

Anyhow, I just compared the retail prices which is without 10$ apart... (around 180$)
Click to expand...
If I get to using my fiber, then I'm probably buying a better switch ;).

Just did the math and that 35.7 is from maxing 24 GE ports, so the Zyxel doesn't take into account your SFP usage either (aside from just a regular Gbic).
 
But you still have more powerful backend even if you don't use all ports :)
//Danne
 
diizzy said:
But you still have more powerful backend even if you don't use all ports :)
Click to expand...
How do you figure? Once your GE port is maxed, it's maxed. If your switch can support them all at max, all at once - what's the point of having spare capacity?
 
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