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General IPv6 Topics => IPv6 on Routing Platforms => Topic started by: bicknell on January 27, 2012, 11:21:40 AM

Title: Apple Time Capsule, more than you wanted to know!
Post by: bicknell on January 27, 2012, 11:21:40 AM
I set up an Apple Time Capsule recently and I'm very pleased with the results.  The unit I set up is a 4th Gen, and is likely the same (with the addition of a hard drive) as the Apple Extreme Base Station.  It's running software version 7.6.

Instructions to set them up for IPv6 are readily available (TunnelBroker will tell you how!), so no need to rehash that set of steps.  The issue I found was with monitoring, no one had documented how the various interfaces were set up.  I did some trial and error, and figuring it out.  Attached to this post is a block diagram of the architecture of one of these boxes.  There are 11 interfaces exposed to SNMP:

mgi0 is the WAN.
mgi1 is connected to an internal 4 port GigE switch that appears to not have any individual pollable ports via SNMP.  The other three ports are exposed on the back of the unit as the LAN ports.
wlan0/wlan1 are the data connections for the 2.4Ghz and 5Ghz radios, respectively.
bwl0/bwl1 appear to be some sort of managmenet interface for the radios.  They report outbound traffic only, never inbound.  Traffic on these interfaces increases as traffic increases on the wlan0/wlan1 interfaces, but at a much lower rate.
bridge0 is a software bridge that sits between wlan0, wlan1, and mgi1 briding the WiFi's and LAN ports together.  Traffic between any two of these three will pass the bridge interface.
pppoe0 is for tunneling PPP over Ethernet, if you use that on the WAN port, basically in that case mgi0 would be with PPPoE overhead, and pppoe0 would be without.
gif0 is 6in4 tunneling, if you have for instance a tunnel broker tunnel.  Again, this would be traffic with no overhead, then as the packets go out mgi0 they would count there with the tunnel overhead.
sth0 is 6to4 (automatic) tunneling.  Again, this would be traffic with no overhead, then as the packets go out mgi0 they would count there with the tunnel overhead.

lo0 is the loopback, not shown in the diagram.
Lastly, there's a SATA port to the disk in a Time Capsule.

I ran the ICSI Netalyzer ( against it (with an HE tunnel configured for IPv6 connectivity) and it basically passed with flying colors.  There are the following minor notes:

Otherwise it passes with a perfect grade, including an impressive performance of not showing any buffer bloat!  Throughput is awesome, I was able to get 500Mbps (yes, half a gig) reading and writing the internal disk from a wired-connected machine.  I've spoken with an Apple engineer before who told me it can easily route and tunnel a full GigE, alas I have no way to test that with this current unit.

Overall, two thumbs up!

Anyway, just leaving this here in case other people are looking for the SNMP info or general feedback.