I ran into an “exciting” bug yesterday. It was seen in a 4500-X VSS pair running 3.7.0 code. When there has been a switchover meaning that the secondary switch became active, there’s a risk that information is not properly synced
Catalyst 3750 IPv6 ACL Limitations
I recently ran into some limitations of IPv6 ACLs on the Catalyst 3750 platform. I had developed an ACL to protect from receiving traffic from unwanted address ranges such as ::, ::1, ::FFFF:0:0/96. The first address is the unspecified address,
Blog Migrated!
Hi! I have decided to migrate my blog from wordpress.com to a private environment. The main reasons being that I felt that I had outgrown the normal wordpress.com site. I wanted to be able to install plugins and get more
Busting Myths – IPv6 Link Local Next Hop into BGP
In some publications it is mentioned that a link local next-hop can’t be used when redistributing routes into BGP because routers receiving the route will not know what to do with the next-hop. That is one of the reason why
More PIM-BiDir Considerations
Introduction From my last post on PIM BiDir I got some great comments from my friend Peter Palúch. I still had some concepts that weren’t totally clear to me and I don’t like to leave unfinished business. There is also
Many to Many Multicast – PIM BiDir
Introduction This post will describe PIM Bidir, why it is needed and the design considerations for using PIM BiDir. This post is focused on technology overview and design and will not contain any actual configurations. Multicast Applications Multicast is a
Petition to Increase Cisco VIRL Node Limit
Cisco VIRL is a great tool but it is artificially limited to a maximum of 15 nodes today. I have created a petition to collect names to send to Cisco, to show that the community really wants to increase this
Interview with CCDE/CCAr Program Manager Elaine Lopes
I am currently studying for the CCDE exam. Elaine Lopes is the program manager for the CCDE and CCAr certification. I’ve had the pleasure of interacting with her online and meeting her at Cisco Live as well. The CCDE is
QoS Terminology – Comparing Cisco to MEF and RFC Terminology
Have you every thought that you knew a topic pretty well but then someone uses terminology that you aren’t used to? People that use Cisco a lot or live outside the MEF world use another terminology than people that are
Using BFD to Track WAN Status and Change HSRP Priority
It’s been five years since I started this blog! Time flies and a lot has happened since. Thanks for being along for the ride. What better way to celebrate than a blog post? This post is going to be short