IPv6 Standardization

24 July 2017 | 1 Comment

The IETF published RFC8200 last week, which officially makes IPv6 an Internet Standard. While this move was a long time coming—IPv6 has now reached about 20% deployment—a more interesting question is: what has changed since RFC2460, which was a draft standard, was published in 2013? After all, the point of moving from the experimental to…

Open19: A New Step for Data Centers

1 June 2017 | Comments Off on Open19: A New Step for Data Centers

While most network engineers do not spend a lot of time thinking about environmentals, like power and cooling, physical space problems are actually one of the major hurdles to building truly large scale data centers. Consider this: a typical 1ru rack mount router weighs in at around 30 pounds, including the power supplies. Centralizing rack…

Network Slices

23 May 2017 | Comments Off on Network Slices

There has been a lot of chatter recently in the 5G wireless world about network slices. A draft was recently published in the IETF on network slices—draft-gdmb-netslices-intro-and-ps-02. But what, precisely, is a network slice? Perhaps it is better to begin with a concept most network engineers already know (and love)—a virtual topology. A virtual topology…

Optimal Route Reflection

17 April 2017 | Comments Off on Optimal Route Reflection

There are—in theory—three ways BGP can be deployed within a single AS. You can deploy a full mesh of iBGP peers; this might be practical for a small’ish deployment (say less than 10), but it quickly becomes a management problem in larger, or constantly changing, deployments. You can deploy multiple BGP confederations; creating internal autonomous…

Reaction: Mend, don’t end, the IETF

10 April 2017 | 3 Comments

Is it time for the IETF to give up? Over at CircleID, Martin Geddes makes a case that it is, in fact, time for the IETF to “fade out.” The case he lays out is compelling—first, the IETF is not really an engineering organization. There is a lot of running after “success modes,” but very…

Distributed Denial of Service Open Threat Signaling (DOTS)

3 April 2017 | Comments Off on Distributed Denial of Service Open Threat Signaling (DOTS)

When the inevitable 2AM call happens—”our network is under attack”—what do you do? After running through the OODA loop (1, 2, 3, 4), used communities to distribute the attack as much as possible, mitigated the attack where possible, and now you realist there little you can do locally. What now? You need to wander out…

Don’t Leave Features Lying Around

27 March 2017 | Comments Off on Don’t Leave Features Lying Around

Many years ago, when multicast was still a “thing” everyone expected to spread throughout the Internet itself, a lot of work went into specifying not only IP multicast control planes, but also IP multicast control planes for interdomain use (between autonomous systems). BGP was modified to support IP multicast, for instance, in order to connect…

Middleboxes and the End-to-End Principle

20 March 2017 | Comments Off on Middleboxes and the End-to-End Principle

The IP suite was always loosely grounded in the end-to-end principle, defined here (a version of this paper is also apparently available here), is quoted in RFC2775 as: The function in question can completely and correctly be implemented only with the knowledge and help of the application standing at the endpoints of the communication system.…

CoDel and Active Queue Management

6 March 2017 | 4 Comments

Buffering packets in a network is both good and bad. It is good because a buffer can hold packets from one stream while another stream’s packets are being processed, to take up and release short bursts of traffic, to hold and then release packets when there is a very short interruption on the wire (or…

OSPF TLVs: Taking advantage of improvements in computing power

25 January 2017 | Comments Off on OSPF TLVs: Taking advantage of improvements in computing power

OSPF was originally designed in an age when processors were much less capable, available memory was much smaller, and link bandwidths were much lower. To conserve processing power, memory, and n-the-wire bandwidth, OSPF was designed using fixed length fields (FLFs). TLVs are more difficult to process than an FLF; to process a set of FLFs,…