According to the RIPE RIS service, the links between MWEB (AS10474) to Telkom South Africa (AS5713) were disconnected on the November 2nd – Telkom being the original transit provider that MWEB used.

MWEB have detected that congestion reduces, therefore service levels increase when traffic bypasses the incumbent and is delivered directly to other ISPs in their region via peering links.  If a network refuses to peer, MWEB simply deliver the traffic to local providers via their international links – possibly just as congested, but available at a fraction of a cost.  If traffic is then delivered to the incumbents via links they themselves pay for, the incumbents also have a financial incentive to peer.

Peering is the best way to encourage enormous capacities between ISPs and other networks, because a direct one-to-one connection can be monitored and well managed in order to guarantee availability for internet traffic.  Peering therefore increases available bandwidth and reduces bandwidth costs.  This will enable high the sort of services that require high-bandwidth availability, like streaming media and high definition video conferencing.

Interestingly, thirty minutes after the adjacency with Telkom was severed, it appeared that MWEB picked up a new transit customer – Yebo, AS12258, with Yebo’s prefixes being advertised to Interoute (again, according to RIPE RIS).  The commercial nature of this downstream relationship is, however, not revealed by the routing table.

The incumbent is perfectly entitled to – and well placed to – sell excellent transit links into the local market, but their strategy to do that, as I explained in my last article, must be to make the transit product in their key regions excellent – this means to peer with the key other local providers (not all providers) in the market, and to ensure that capacities across their backbone and to customers are well managed and available for traffic.

It demonstrates clearly that deregulated markets offer enormous advantages over controlled ones, and should serve well as a reminder to operators and policy makers that simply getting out of the way could be the best way to further their aims for industry in any given region.  This is mainly because:

• Allowing networks to interconnect freely (calculated as number of active ASNs in a region), and the size of the market (calculated from the pool of announced ip addresses in a region) are strongly correlated (slide 8).  My guess is that more organisations get online, because competition leads to price falling, whilst the versatility and relevance of services offered increases.
• When there are a larger number of networks in a region, the global carriers have a greater incentive (more customers!) to run diverse connectivity into the region.  This leads to a huge advantage to firms in a region, their connectivity carries on despite local major fibre breaks. (slide 25, 36)
• Content moves out of the US/Western Europe and into the local market place, creating opportunity (and jobs) for local players, and improving the performance of services for local users.

Incumbent networks in this region have a huge opportunity to grow revenues, as the market expands, as long as they are willing to interconnect widely in this region.  As the number of providers in a region expands, customers will be able to (and, according to this research, actually do) pick between innovative and disruptive new providers with excellent regional (via peering), and international (via transit) capacities.  Peering also makes capacity cheap, because traffic can stay local to the ISP.  An incumbent provider that refuses to peer in order to retain market share will not be able to compete in quality terms with the new providers.  Defending a 100% market share is impossible in a competitive market, so the strategy must change, the aim must become enjoying the fruits of a booming market instead of monopoly.  As the Renesys slides say, there is no dominent IXP in this region yet, with many networks dragging traffic to London, Amsterdam or Frankfurt to exchange, but this will change as the density of providers in the Middle East reaches a critical mass.

Setting up an Internet Exchange point is simple from a technology point of view, but requires significant planning, and community support for the plans.  Read the slides to find out more about what must be planned.

Download:  [Slides + Notes (recommended)] ~ [Slides alone]

View directly from Slideshare (requires flash):

A route-server is a fantastic way for networks to start to peer (swap internet traffic) at Internet Exchanges, and results in instant success after connection.  A network with an open peering policy can connect to the internet exchange, and then get peering with more than half of all the other networks on the exchange by bringing up a single pair of BGP sessions.

When a route-server peering is established, a BGP session is setup between your router and LONAP’s route database.  LONAP advertise all of the prefixes of the other connected members to you, but the traffic between you and the other members flows between you and your peer directly (it does not need to traverse the route-server.)  Members do not need to open their network to their own customers at the route servers, they can send special messages to the route-servers to prevent certain networks from seeing prefixes.

Route-servers are not new, but have had a bad reputation for stability for several years.  With our colleagues at several other community exchanges, including the LINX, we shared bugs, workarounds, and feature requirements with each other and the main open-source route-server vendors.  Eventually, we were able to report considerable improvement in stability last December.  As a result, we at LONAP selected BIRD and OpenBGPd as our route server vendors, and built a support framework to link our configuration with the LONAP configuration system.

Since then we have been advocating the route-servers to our members, and the fact that they are now providing a stable stepping-stone to more than half of our peers shows that this effort was worthwhile.  If you would like to start to peer, but need to be assured of instant success and results, then contact Andy for information about how the route-servers at LONAP can help.

Since January 1st, a few key milestones have passed, indicating how urgent the IPv4 rundown problem has become. Firms that rely on internet connectivity must take urgent action in light of the events:

• The allocation last week of two further /8s (blocks of IPv4 addresses with the same number before the first dot) to APNIC mean that for the first time, less than just ten percent of the IPv4 unallocated pool is available to be assigned.  At current utilisation rates, this pool will be exhausted in only 600 days.  Of course, the internet could stop growing, but all signs point away from this…
• The allocation of 1.0.0.0/8 is the assignment of the first really ‘dirty’ block of addresses, signalling that we really are in the run-down period.  Bad network design decisions in the past have meant that networks have ‘borrowed’ the use of addresses starting 1. for ‘internal use only’ or special applications on their network.  This means that organisations assigned address space starting ’1′ may well have partial connectivity even though they are rightfully assigned the space.  Examples are the braindead hotspot operators who take addresses like 1.1.1.1 to trigger hotspot logout, but a handful of examples appear across this address range.
• RIPE NCC, the organisation who assign addresses to networks in and around Europe have this month implemented their ‘run down’ policy which will mean that organisations requesting space will only be able to cater for their growth requirements for a very short amount of time.  This is to evenly spread the inevitable misery across the ISP community.

RIPE members should thoroughly audit their address space so that they can ensure that their records are accurate, because RIPE are more likely to ensure that address space is assigned to your end users in line with the community’s policies.  ISPs and services providers who need help can contact me for further information or specific assistance.

Organisations who rely on internet connectivity for their products should ensure their providers have an IPv6 migration plan in place.  Otherwise end-to-end connectivity for your home or office is unlikely to be something you can enjoy looking beyond the runout period.  Companies hosting network services, for example a website, should enquire what their host’s IPv6 plans are, and start to enable their services via v6.

There is real traction to ensure v6 support appears in both the hardware and services you need to connect to the internet.  It is easier today than before to find help making your services available via v6.  The alternatives – patchy connectivity via nested stacks of ipv4 islands, or no more end-to-end connectivity (so that your internet service is a walled garden), have much worse consequencies than learning to roll v6.

Engineers know the facts by now and have no excuse.  For more information, see the RIPE NCC’s information site, ipv6actnow.

The slides show that the new route-servers perform splendidly well compared with traditional Quagga based MLPs, also that route-servers are now free of ‘first generation code’ bugs, and also that they handle your prefixes transparently – as you would expect.

Interestingly, BIRD and OpenBGPd behave identically ‘on the wire’ so IXPs are encouraged to use multi-vendor MLP on their platform for increased reliability and stability.  The new breed of route-server code is dependable and tested, so networks that would like to connect should draw confidence from this testing, and IXPs wishing to roll out MLP services should feel confident in the software tested.

Happy peering!

The messages are clear and simple.  Working now to get ready for the IPv6 transition will be less expensive and lower risk than waiting for IPv4 starvation to hurt.  I interviewed some key enterprises about their specific grumbles but the great news is that most are transitional and already people are working on fixing them.

It covers :

• Provisioning tools/notes
• SNMP
• NetFlow notes
• Scripting notes

Some history in very brief terms – all networks on the internet that participate in BGP need a number to identify themselves.  On the public internet, this number normally needs to be globally unique.  The number can be between 1 and 65,535, and we have close to 50,000 of these numbers in use.  To grow past this number, the BGP standard needs to be modified.  The modification is described in a document called rfc4893, and this document was accepted by the community last May.

The first incarnations of router software that support these large AS numbers is now circulating. Due to flaws in the standards that exist in January 2009, if you install one, you may become disconnected from the internet.

Why? Some more background, first: BGP allows for large networks to configure ‘hints’ in their router configuration, by dividing their network into several small networks (confederations).  The information about the ‘virtual’ divisions of the network should be removed from the BGP messages which are sent to other networks, but if a network supports large ASN in some parts, and not in others, the routers in the legacy part of the network may not know to test the ‘large number’ section of a BGP message for the presence of an internal confederation ID.  The standard tries to take this into account by explicitly forbidding that confederation ID be passed between networks in the asn4 part of the BGP message.

However, should this occur by accident, what are the effects?  Well, elsewhere in the Large ASN standard, it states that the connection between two networks should be severed if Confederation ASN appear to be leaked in the ASN4 part of the BGP message.  This means that networks which do not understand large ASN can forward a broken message to a network which does understand large ASN.  At which point the network which does understand large ASN should tear down the session.

Since this message can be delivered over a transit session, this means the receiving ISP loses their connection to the internet via that ISP.  If it learns the router over every ISP, then the network can lose its connection to the internet entirely.

The message that I reported was leaking in December is still leaking.  AS196629 (AS3.21 in legacy asdot notation) is announcing to AS35320, who are not stripping their confederation information from the large-asn section of BGP messages.  If you learn the prefix via AS196629′s other transit, AS6886, then you are fine.  If you learn the prefix via AS35320, you are (today) receiving a broken message.

We tested out how Cisco IOS is coping with this broken message using the first generation of code for the cisco 7200 router that understands ASN4.  We peered the router to NetSumo‘s research and development network, AS15653.  Cisco honours the standard/rfc, and breaks the session.  Since it learns the dirty message on the transit session, the router disconnected our test network from the internet entirely :

• *Jan 16 11:29:58.531: %BGP-5-ADJCHANGE: neighbor 193.239.32.2 Up
• *Jan 16 11:30:02.595: %BGP-6-ASPATH: Invalid AS path (65044 65048 65062) 3.21 23456 received from 193.239.32.2: Confederation found in AS4_PATH
• *Jan 16 11:30:02.595: %BGP-5-ADJCHANGE: neighbor 193.239.32.2 Down BGP Notification sent
• *Jan 16 11:30:02.595: %BGP-3-NOTIFICATION: sent to neighbor 193.239.32.2 3/1 (update malformed) 27 bytes E0111803 030000FE 140000FE 180000FE 26 FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFF 0050 0200 0000 3540 0101 0240 020C 0205 3D25 2114 89F8 5BA0 5BA0 4003 04C1 EF20 02E0 1118 0303 0000 FE14 0000 FE18 0000 FE26 0202 0003 0015 0000 5BA0 175B CFDA

If you work in this field, I implore you to read the more thorough analysis on the nanog list, and participate in the discussion to work out how we should correct the standard, to allow routers to behave differently when a dirty message is received.  If we do not, then there is a simple, easy to understand, and easy to implement mechanism to break the internet, as soon as networks upgrade to the current version of their routing software.

There is a feature that requires agents to press # when they are ready to speak to a caller.  Since we forward calls to agents via their mobiles, rather than auto-answer calls in a desk environment, we disabled that feature with ackcall=no in agent.conf.

After upgrading to 1.4.22 we see this configuration is nolonger honoured.  Diffing chan_agent.c between version 1.4.21 and 22 shows a new section of code saying (in English) that ‘if there is no per-channel override specified in the dialplan, default the configured variable’ (line 2048).  I looked at where the default was read from the config file and it looks like a lot of different chunks of chan_agent want to set the ackcall default!

The bug shows up in the asterisk console as :

– Agent/xxx is ringing
– SIP/voip-out-081e5a88 is making progress passing it to Local/447xxxxxxxxx@uk_all-a667,2
– SIP/voip-out-081e5a88 answered Local/447xxxxxxxxx@uk_all-a667,2
– Local/447xxxxxxxxx@uk_all-a667,1 answered, waiting for ‘#’ to acknowledge

The workaround is that the only safe place to set the default ackcall behaviour is for each channel in the dialplan.  If you want to disable the ‘waiting for ‘#’ to acknowledge’ behaviour, configure your dialplan as such :

exten => 1701,1,Answer()
exten => 1701,n,Set(AGENTACKCALL=no)
exten => 1701,n,Queue(noc|r|||40)
exten => 1701,n,Voicemail(xxxxx)
exten => 1701,n,Hangup