Nexus slow SCP and jumbo frame failure
If you’re attempting to use SCP on your Nexus switch and you realize you’re getting slow performance, even with jumbo frames enabled on your source interface, t...
Category: Networking
Understanding Cisco config register
Let’s just get down to business, we all use it but few of us understand what any of it means. The documentation is a little, well, complicated for some people s...
Cisco BGP EVPN VXLAN – Part 2 – Spine uplink failure
So, you’ve surely seen some interesting tidbits in the previous section, things you haven’t noticed from other configurations on the Internet. I will outline wh...
Cisco BGP EVPN VXLAN- Part 1
Here is an overview of the Cisco implementation for VXLAN using BGP EVPN for distributed control-plane operations. anycast gateway, and unicast head-end replica...
Object groups in Nexus
Much like on firewalls you can create object groups in Nexus, which you can utilize when you’re implementing ACLs object-group ip address {OBJECTNAME}{subnet/ma...
Cisco MST 802.1s
All Cisco switches by default have PVST+ as their spanning-tree protocol (mode). PVST+ is Cisco proprietary and, in my humble opinion, should never be used in a...
Vmware load balance hashing with Nexus vPC ICMP unbalanced
There is an issue I have noticed with VMware systems deployed with Nexus vPC technology that involve traffic only making it out of the vPC by disabling half the...
Etherchannel load balancing – Explained
It is a common mistake to assume X number of ports in an etherchannel equates to the common port speed * X; however, this is grossly incorrect and I’ll attempt ...
Find CDP traffic on your Linux box
You can use tcpdump or wireshark but if you have a Linux box handy you can install: cdpr. It makes life easy like this: cdpr -v Just follow the prompts for sele...
Capturing DCHP with Wireshark
We’ll just do it the “quick and dirty” way. Just start capturing all traffic on an interface. Now, in the top portion by the word “Filter:” put this syntax in: ...