Friday, May 12, 2006

D-Link and The NTP of Death Part Deux

(from an update at Poul-Henning Kamp's site)

"D-Link and Poul-Henning Kamp announced today that they have amicably
resolved their dispute regarding access to Mr. Kamp's
NTP Time Server site. D-Link's existing products will have
authorized access to Mr. Kamp's server, but all new D-Link
products will not use the NTP time server. D-Link is
dedicated to remaining a good corporate and network citizen."

Since the existing products will have authorized access to the server, they're probably buying the bandwidth for him (as part of his original suggestion). And D-Link will presumably not harvest any more Stratum 1 NTP server addresses...

PS This update did occur a while back, I only noticed it now.

RIPE vs route-flap damping

RIPE has issued ripe-378

It suggests that 2 major problems arise from implementation of route-flap damping:

1) Impeded convergence
Basically a ripple effect, caused by the flap penalty with a change in BGP attribute (in this case, a new path to the same AS). The prefix probably has not been withdrawn from the routing table at all, but route-flap damping can be triggered at the 2nd remove - i.e. at the neighbour of the router/AS making the routing change. Not mentioned, but tunable on some implementations, is that attribute changes can incur a lower penalty than straight prefix withdrawals. This could help alleviate local problems, but will start causing inconsistent (and difficult to diagnose) path selection.

2) Transit of updates
Related to the consistency of implementation of RFD: timing of routing updates. Because of differences in the Minimum Route Advertisement Interval (MRAI) Timer (the amount of time a router waits before passing on a route update), as well as differences in paths, multiple updates for the same 'flapping' AS can arrive at a router many hops away and cause multiple updates as the router evaluates the new routes available. This can easily trigger flap damping. There have been actual measurements where this resulted in a single prefix withdrawal producing 41 BGP events a few hops away!

Result: ripe-378 recommends against RFD, citing higher router CPU power as able to cope with flap events without damping.

Yay Stupid Network!

Wednesday, May 10, 2006

Big Brother's crackdown on crime

FM has an interesting sidebar in the current issue.

All SIM cards and phones that are sold or given away must have a paper trail: a record of the recipient's name and address and a photocopy (old skool!) of the recipient's ID!

Of course, post-paid (i.e. contract) users already have this in place courtesy of their Service Provider taking down their details to ensure payment.

"The measures are part of a security crackdown on the use of cellphones in crime , security officials say"

I wonder what the penalties for non-compliance are? Gareth, David, Herman: I'm talking to you here! You don't have photocopies of my ID and probably don't know my exact address. And I've got your phones! HAHAHAHAHA. I am a criminal genius!

PS Vodacom wants to use an electronic form for their customer registration. Mmmmm...electronic photocopies...

PPS [For extra credit] How many pre-paid cellphone users are there in South Africa?

Cell C number portability

Cell C has a small FAQ on Mobile Number Portability

Interesting points
1) MNP will take effect on 1st July 2006
2) No mention is made of offers to buy subscribers out of current contracts with competing networks. So much for customer acquisition. Maybe Virgin will be more proactive.

At least we don't have some of the crezzy US problems like GSM vs CDMA, BREW vs Java, etc etc