Networking

There are 5 posts filed in Networking (this is page 1 of 1).

getting VLANs working between Cisco & HP gear

Ever since I started at Devlin, I’ve had one nagging problem with the network gear: the VLANs from the Cisco equipment (a triad of Catalyst 3550-24 switches) won’t propagate to the other gear we have (an HP ProCurve 2424M and a Linksys SRW2024). I read all I could about VLANs and tagging, but no matter what I did I couldn’t get the non-default VLANs to show up on anything but the Cisco gear. I figured I was missing some key information, particularly about when to tag and not tag VLAN traffic, that was preventing me from getting this working.

I finally did a search on Google about Cisco interoperability, and found this page which indirectly made everything clear. It turns out that the tagging on the HP (or any other switch being connected to the topology) needs to be done as follows:

  • set traffic on the trunk port to be tagged for every VLAN you want to propagate
  • allow access to the VLAN on the non-trunk ports but set them to be untagged

I was originally a little worried because the VLAN I’m interested in propagating is the voice VLAN (for our IP telephony setup) and I feared that the Catalyst would do something really weird with it (seeing as how you specify switchport voice vlan 2), but it seems to be just another VLAN. I assume the foregoing IOS directive is just for QoS or something on the Catalyst.

By the way, doesn’t the University of Wales’ IT department have an awesome name? I know it’s Gaelic, but I should start calling my department Gwasanaethau Gwybodaeth too. That would certainly cut down on the help tickets — I could start saying “please e-mail [email protected] to open a ticket” 🙂

the Internet was borked today

What a day — Rogers’ network was b0rked starting around noon, which meant that our office T1 connection flapped up and down all afternoon. It finally seemed to give out entirely around 4 p.m., at which point I think everyone at the office just headed home. Since I have my name on a ticket with Rogers, I’ll definitely be asking for a refund per our SLA.

Matt, a former colleague of mine, told me that Bell had been advertising null routes in the morning too — not good. In general, not a good day for Canadian ISPs.

In other news, I’m working on the Asterisk VoIP server again. As I build and configure this thing, I think it’s best if I keep a list of questions that I will try to answer as I progress. Here’s my current list of questions. If you are an Asterisk guru and happen to know the answers to these, feel free to comment on this post!

  1. Actions in the dialplan are usually applications. Where does one find a list of these applications (and what they do), short of doing a show applications at the Asterisk CLI?
  2. What is the syntactical format of each exten => line in the dialplan? (I know I’ll probably come across this somewhere in the docs, eventually)
  3. How do I register phones — either softphones or physical IP phones — in Asterisk, and how do I get those phones to authenticate to the Asterisk server to self-register themselves? Is there any way to autoregister phones with a restricted dialplan?
  4. How do I know what all the sounds bundled with Asterisk say, short of playing them one-by-one?
  5. How do I configure the voicemail system to do things like e-mail voice messages to the mailbox owner, encode the voice mail in different formats like Ogg Vorbis or MP3, and so on?

I plan to post the answers in this journal when I find the answers.

home router replaced!

I finally decided to replace my FreeBSD-based Sun Ultra 10-based home router. There were a couple of reasons for this:

  1. I was running FreeBSD 5.x, which meant that the keyboard wouldn’t work — I could only control the system remotely over SSH or through a serial console. This was fixed in later versions of FreeBSD 5.x but I didn’t want to bother upgrading, since the box isn’t the fastest machine
  2. Using a desktop workstation for routing and running ppp consumes more power than it’s worth, and makes a fair amount of noise
  3. Using an 400 MHz UltraSparc III-based workstation with 512 MB of ECC RAM for a simple firewall and router seemed like a bit of overkill 🙂
  4. I want to free up the Ultra 10 for testing out Solaris 10 and possibly upgrading my Solaris 9 SCSA designation.
  5. I want to (finally!) equip my home with wireless… yes, I’m a little late getting on the bandwagon.

Continue reading →

something lost in translation

Company name of the offender removed for their protection (they’re already in Chapter 11 – no need to help them along here)

Dear valued customer,


On the 25.November 2003, 11:35 we had a route leakage. Due to a mistake on the -------- backbone, we anounced to many routes.


For this reason many peering-sessions were closed automaticly. Issue is resolved. Situation is going normalized.

Regards

[deleted]

Heh. "Situation is going normalized" — I have to use that one in resolving RT tickets.

IP block renumbering day

… it’s only our internal 10.10.10 netblock, but still, a lot of grunt work.

I managed to reconfigure all the switches without locking anyone out (or myself), and MRTG didn’t complain that much. All that remains is to renumber the dev server, and hopefully doing a perl -p -i -e 's/10.10.10.20/10.10.10.5/' /etc/* will do the trick.

Then the IT department can appropriate that new Cisco (the one which has about 4 out of 10 ports in use, when a bunch of bimaps on our firewall could do the trick) for ourselves 🙂