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.

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.

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.

Lee’s premise is that “Certainly Skype is not a walled garden. All things being relative, it’s certainly not overly closed either.”  Lee claims that the accusations of closeness are unfair, because they are levied by commentators who advocate SIP based addressing and dialing rather than any other system.

This is not my premise.  I claim that Skype is closed because calls are signalled and completed using protocols that are entirely secret as a matter of policy.  Skype’s founder presented at Spring VON 2007 and stated that if Skype did not keep their protocols entirely secret, then Skype would be full of spam and attack like email is.  I think this is a poisonous claim, telephone networks have been interconnecting around the world since telephony was conceived.  By not allowing telecoms firms to interconnect between the skype namespace and other networks, Skype have prevented openness to develop and maintain a monopoly position. That’s perfectly acceptable business, but it is not in the slightest bit open.

Randy Bush googled Walled Garden for a recent presentation and found this cartoon.  I like this definition because it’s correct.  Is Skype a Walled Garden ?  Lee says a Walled Garden is a commercial restriction, for example, “sharing of ringtones via Bluetooth, using WiFi from a PDA, having access to all Web sites“.  I think that only allowing interconnection with the purchase of an upgrade like SkypeOut is a restrictive or practice that suggests Skype is a Walled Garden.  Worst of all a call between two VoIP networks using this method requires default PSTN routing, which harms signal quality, and prevents the expansion of next-generation services such as Wideband/High Definition audio.

The meshing of networks, whether they are traditional voice or IP networks, leads to higher audio quality and increased reliability.  Keeping telephony systems and protocols secret in order to prevent meshing may well be a viable business model, but it is not an open business model.

AS196629 (3.21 in asdot) announce 91.207.218.0/23.  Experienced eyes will notice that this is quite a large as number.  It’s a ‘new’ 4-byte ASN.  When an OpenBGPd speaker with 4-Byte ASN support receives the update for this message, the session is torn down with the daemon logging a ‘fatal error’. Why?
OpenBGPd is checking AS4_PATH to ensure that it contains only AS_SET and AS_SEQUENCE types, as per RFC4893.  When processing the UPDATE for 91.207.218.0/23 it sees :

91.207.218.0/23
Path Attributes – Origin: Incomplete
Flags: 0×40 (Well-known, Transitive, Complete)
Origin: Incomplete (2)
AS_PATH: xx xx 35320 23456 (13 bytes)
AS4_PATH: (65044 65057) 196629 (7 bytes)

See the confederation ASNs in the AS4_PATH ?  Thats forbidden :

To prevent the possible propagation of confederation path segments outside of a confederation, the path segment types AS_CONFED_SEQUENCE and AS_CONFED_SET [RFC3065] are declared invalid for the AS4_PATH attribute. RFC 4893.

The RFC does not suggest how to handle AS4_PATH violations, but if the bad path is learned on every upstream, this will cause a network with obgpd edges to disconnect from the internet…. Modifying the OpenBGPd software to permit AS_CONFED_SEQUENCE, AS_CONFED_SET in an as4_path causes the path to be accepted and the session is not torn down.  This isn’t a great fix.
The impact today is fairly limited as there are relatively few bgp speakers honouring the 4-byte ASN protocol extension rules, but as code that support these features creeps around the internet, the next time this happens the impact could be much greater, so we need to understand which implementation of which BGP software caused this illegal origination.

From a software point of view, I want to see a configurable option to reject the route but keep the session, reject the route and drop the session, accept the route but log/send trap, etc.

In any case we need to publish the arrangement that has led to this mistake so that other networks using the same toolset to originate prefixes can avoid the same situation happening.  I have made contact with an engineer at the NOC who are investigating.

• IPv4 addresses are scarse, and at current consumption rates, the IANA pool of free v4 addresses will be gone at the start of 2011.
• This starts a “Post IPv4 world” where the IPv4 internet continues to function as before (certainly initially), but obtaining new addresses becomes harder and expensive.  This inhibits expansion of existing firms, and new entrants to the market.
• Address trading is likely to lead to a larger routing table, meaning that failure-recovery times increase, and the risk of blackholes on the internet increases.
• Large broadband providers may not have enough v4 addresses to give one address per customer.  This means protocol translation techniques need to be used, which break the end to end model.  We rely on the end to end model when innovating new services on the internet.
• If services and consumers gradually roll v4 and v6 (dual stack), the negative impact of markets for addresses, routing problems, and translation can be mitigated.
• Service providers are enabling v6 in the core.  Enterprises need to move next in order to get the world v6 ready.

The advice I gave was :

• Today’s market leaders are already learning v6 lessons in their labs, (e.g. ipv6.google.com).  They are doing this to help them retain market leadership.  If you want to retain your market position, start labbing your applications and service provision with v6.
• Write a policy stating all new purchases of infrastructure and services need to be from providers with v6 support, or a well defined v6 road map.  In other words, make v6 a “life cycle upgrade”.
• Share information, and learn information from your industry peers.
• I also listed some advice to developers with regard to v4 and v6 differences.
• I then delivered a very quick primer to those who have not seen v6 deployed before.

My hope is that this talk is improved upon and delivered internationally to enterprises.