Extreme 5520

Tested the new Extreme 5520 universal switch this week, which supports EXOS (default) or VOSS. VOSS does not support stacking so was a learning experience creating a stack of EXOS switches for the first time.

Stacking is quite straight forward and can be simplified by using easy-setup when run the enable stacking command on the master switch where I consoled onto. It is recommended to create a ring topology before doing this step.

After powering on the first switch I saw a message advising me to upgrade the software version.

I configured a management VLAN and gave it an IP address and moved a port into the VLAN for my laptop. I initially used TFTP to upgrade the XOS version but for the remaining switches I used a USB disk on USB2 at the rear.

Insert a USB in the USB slot and type show memorycard to make sure the USB is recognised.

Type ls /usr/local/ext to list the files on the USB disk. Enter download image memorycard summit_arm- to upgrade from USB instead of TFTP which is much quicker.

It is good practice to upgrade the software and ensure all switches are using the same release before stacking them.

Used 0.5m QSFP+ Passive Copper Cables 40GB to connect stacking ports at the front of the switch.

Inserted 5520-VIM-4X 4x10GE SFP+ in two different switches and created a static lag group with two ports (one from each VIM). See Extreme website for list of SFP/SFP+ supported in the VIM module.

enable sharing 1:57 grouping 1:57,2:57 algorithm address-based L2

When enabled RADIUS mgmt-access I could no longer SSH into the switch. I expected it to work and fallback to use local accounts as I had no RADIUS server to test with but was surprised to get access denied. To workaround this issue I created a fail-safe account and permitted SSH for it and then I could login when RADIUS was not connected.

Scapy QOS Ping

Example below uses Python Scapy module to generate an ICMP Request with the TOS value 184 (DSCP 46/EF) which is useful for testing QOS.

from scapy.all import *


Can run from Python 3 in Windows. Open two Python 3 instances and send an ICMP packet with tos=184.

In the second session use the following to see sniff and filter on the interface and check the TOS field of the ICMP response.

from scapy.all import *

sniff(iface=’eth0′, filter=’icmp’, prn=lambda x: x.show())

Type show_interfaces() to list the network adapter names and replace “eth0” with the description of the adapter you wish to sniff.

If you get an undefined literal error it maybe due to the way the above example is copied and pasted so pay attention to the use of double or single quotes.