Bailey's Comet at Moorgate

A London Underground Engineering train has been parked up at Moorgate station recently. As I'm a self-confessed train nerd I got off to take some photos - alas I'm not much of a photographer. 

The Roundels on the side says "Bailey's Comet" And I'm reliably informed it's a rail grinding train for smoothing out irregularities in the tracks. 

This engineer train is powered by electricity from the rails like a standard tube train, however some exist that are battery powered for when the current is off for maintenance. 


Using a Cisco 887 Router as a VDSL Modem

I've had a Cisco 887 Router lying around gathering dust for a while and thought I'd put it to use as a VDSL Modem, replacing the existing Openreach box. In theory this will give me more visibility on line stats allowing me to do more logging and troubleshooting.

I tried it a while ago but had some MTU issues so it was banished back into storage. My ISP, Plusnet support 'Baby Jumbos' of 1508 Bytes which allows for a 1500 Byte frame + 8 Bytes of PPPoE overhead, so this time I configured the relelvant interfaces with a 1508 Byte MTU and its working nicely.

The configuration is pretty basic, partly due to limitations of the router. Ethernet0 (The DSL port) has a subinterface for Vlan 101 which is required by the VDSL infrastructure supplied by Plusnet / BT. Vlans 1 and 101 are transparently bridged to allow PPPoE passthrough, and I've added an IP on the bridge for management with some access lists for security.

The configuration is below. I can't make any guarantees it will work or it's secure, and I've redacted some of the sensitive information. Hopefully someone will find it useful or make suggestions for improvements.

Flat CAT6 Cable

I recently purchased some Flat CAT6 Cable for a grand total of £4.64 for 15M from Ebay with the intention of passing it through some double glazed window seals. When it arrived I was slightly taken aback at just how thin the cable was, around 6mm wide and 1.5mm thick. Great for squeezing through a tight window seal, but perhaps not so great for pushing packets.

2p for scale

To see if my scepticism was warranted I ran some iperf tests, and at 925 Mb/s I can't fault it-

C:\Users\matthew\Documents\iperf-3.1.3-win64>iperf3.exe -c -b 1G
Connecting to host, port 5201
[  4] local port 57144 connected to port 5201
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-1.00   sec   100 MBytes   843 Mbits/sec
[  4]   1.00-2.00   sec   101 MBytes   846 Mbits/sec
[  4]   2.00-3.00   sec   112 MBytes   941 Mbits/sec
[  4]   3.00-4.00   sec   113 MBytes   947 Mbits/sec
[  4]   4.00-5.00   sec   112 MBytes   944 Mbits/sec
[  4]   5.00-6.00   sec   113 MBytes   946 Mbits/sec
[  4]   6.00-7.00   sec   113 MBytes   947 Mbits/sec
[  4]   7.00-8.00   sec   113 MBytes   946 Mbits/sec
[  4]   8.00-9.00   sec   113 MBytes   947 Mbits/sec
[  4]   9.00-10.00  sec   113 MBytes   945 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-10.00  sec  1.08 GBytes   925 Mbits/sec                  sender
[  4]   0.00-10.00  sec  1.08 GBytes   925 Mbits/sec                  receiver