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sjwrick
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Fragmentation Errors where to start

Thu Nov 01, 2012 6:35 pm

We have a RB11ah (ROS 5.19) running as a bandwidth box.

UbiquityPowerBridge <---> switch <--> RB1100AH port3/Queueing/Port4 <--> RB1100 (ROS 5.19)

Also have a x86 (ROC 5.13) slaved off the switch for hotspot customers.

We are only able to produce a variable 3-8 MMbps through port 3. When inserting a switch between the RB1100ah and the rb1100 we produce 50-60Mbps++.

The port3 shows fragmentation errors. We switched to using a different port (port11) on the RB1100ah and see no errors and speed to great!

Where can I start resolving the port3 issues?

Thx.
 
jandafields
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Re: Fragmentation Errors where to start

Thu Nov 01, 2012 8:40 pm

We are only able to produce a variable 3-8 MMbps through port 3. When inserting a switch between the RB1100ah and the rb1100 we produce 50-60Mbps++.
So, it looks like you are saying that PORT-3 gets 60Mbps when you insert a switch between the to routers??? Is that accurate?
 
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sjwrick
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Re: Fragmentation Errors where to start

Thu Nov 01, 2012 10:12 pm

No port3 gets 3-8M and Fragmentation Error (connected to a switch)

When I abandon port3 to another port, port11, instead I get +60MB - same switch and no Fragmentation Errors.

Rick
 
jandafields
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Re: Fragmentation Errors where to start

Thu Nov 01, 2012 10:49 pm

EXACT IDENTICAL SAME settings and rules and config for port 3 and 11 ?
 
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sjwrick
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Re: Fragmentation Errors where to start

Fri Nov 02, 2012 7:44 am

OK so the l2mtu is 1598 for the error prone port3 and 1600 for port11 (see below)

name="eth3" mtu=1500 l2mtu=1598 mac-address=D4:CA:6D:3F:27:CC arp=enabled auto-negotiation=no full-duplex=yes speed=100Mbps master-port=none bandwidth=unlimited/unlimited switch=switch2

name="eth11" mtu=1500 l2mtu=1600 mac-address=D4:CA:6D:3F:27:D4 arp=enabled auto-negotiation=yes full-duplex=yes speed=100Mbps

Looking at the ports these are default values.

Ports 1-10 are the same l2mtu=1598
Ports 11-13 are the same l2mto=1600

AND I have
port3 auto-negotiation=no
port11 auto negotiation=yes

So I toggled auto-negotiation on port11 to no AND.................. Fragmentation Errors start piling up.
Huh.

I've been following some threads that led me to turn off auto-negotiation when connecting to Ubiquity radios. Some talk of a chipset not working correctly on 450Gs and/or 493Gs. And I experienced some ports switching to 10MB with auto-negotiation on. So I've been turn it off on both the router and radio.

Looks like it is not a fix all policy. This is a RB1100AH connecting to a Netgear 10/100 16port switch.

OK tomorrow more testing.

Thanks!!!!

Rick
 
jandafields
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Re: Fragmentation Errors where to start

Fri Nov 02, 2012 2:28 pm

The differing MTU's are likely the problem.

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