Category: Network Engineering

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Moving to the dark side

Things have been crazy this past year. After 10 years of working at my old job, last march I took a position at a new job. I am moving from working as an engineer working on IOS and IOS-XR service provider networks, to now working in the Healthcare industry at a regional health care provider.

One of the biggest technical differences, which I was and am excited about was being to be able to work with a platform I have been watching for awhile. I am now moving over to the dark side….

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Yes, I have been watching Junos and noticing how IOS-XR which I was growing fond of seemed to mirror many Junos examples I saw. In addition to working with Juniper devices, but I am working on F5 load balancers and Infoblox IPAM. I am planning to work on some more post in the next few months and modify some of the drafts I had from earlier to be non-vendor specific. I also may also start adding articles that are not about networking at all, as I may be posting things related to my interest and work with audio and recording.

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BGP workaround for backbone issue

I had an interesting issue where I had to use BGP traffic engineering to work around an unusual quark with a major backbone provider. The site I was working with was dual-homed using a major national provider and a smaller local provider. In order to better load traffic between the circuits we attempted to use some BGP as-path prepending to favor the major connection less. When we added more than two prepends to the major provider, all traffic on the link stopped and we only saw about 4kbps to traffic on the link.
Continue reading “BGP workaround for backbone issue”

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Mercurial for Tracking Cisco Configs

As I have been working with different routers I have squired a small repository of configuration files that I use for examples, backups, and ways of remembering the way the network was set up before a change. At the start I maintained each config as a separate file, usually containing the date (i.e. router1-071012.cfg). While that worked for a while it got cumbersome when I wanted to track more than one legacy version of a config file. Continue reading “Mercurial for Tracking Cisco Configs”

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Allowing UNI or protected ports on Cisco switch to reach each other using IP

When deploying Metro Ethernet service and Colocated services, best practice it to put the ports in protected mode or uni. This is to prevent customers from causing interference to each other with layer2 protocols. It also allows the user of service provider traffic filtering. The downside is without additional configuration, customer traffic to another customer is blackholed when they exist in the same subnet. Continue reading “Allowing UNI or protected ports on Cisco switch to reach each other using IP”

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Editing Cisco ACLs Inline

Are you annoyed at having to copy an ACL to a text editor to add a line?   After that, you have to either remove the ACL entirely or add the new version with a different name and update all the interfaces to use the new name.  I have been using the following trick recently to edit ACLs inline without having the complete remove or rewrite the ACL.
Continue reading “Editing Cisco ACLs Inline”

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Setting up 802.q and switch ports in an ASR9000

IOS-XR has a structure that is very different than standard IOS. I would recomend checking the different documentation at Cisco.com this post is not going to explain things like having to commit a config before it is applied… etc, but rather I am going to assume you have read the getting started guide.

The project that lead to me being exposed to an ASR9000 is a network migration that is replacing a pair of 7200 routers and a 3750 switch (which is only being used for layer2 features) with a single ASR9000 with Redundant RSPs. The ASR has a 40 port gig module and a 4 port 10 gig module. To replace the switch I need to add ports to a “vlan” and trunk those vlans to downstream switches at other pops. Continue reading “Setting up 802.q and switch ports in an ASR9000”