HPACK: the silent killer (feature) of HTTP/2
If you have experienced HTTP/2 for yourself, you are probably aware of the visible performance gains possible with HTTP/2 due to features like stream multiplexing, explicit stream dependencies, and Server Push.
There is however one important feature that is not obvious to the eye. This is the HPACK header compression. Current implementations of Apache and nginx servers, as well edge networks and CDNs using them, do not support the full HPACK implementation. We have, however, implemented the full HPACK in nginx, and upstreamed the part that performs Huffman encoding.
CC BY 2.0 image by Conor Lawless
This blog post gives an overview of the reasons for the development of HPACK, and the hidden bandwidth and latency benefits it brings.
Some Background
As you probably know, a regular HTTPS connection is in fact an overlay of several connections in the multi-layer model. The most basic connection you usually care about is the TCP connection (the transport layer), on top of that you have the TLS connection (mix of transport/application layers), and finally the HTTP connection (application layer).
In the the days of yore, HTTP compression was performed in the TLS layer, using gzip. Both headers and body were compressed indiscriminately, Continue reading
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34 – Q-in-VNI and EFP for Hosting Providers
Dear Network and DCI Experts !
While this post is a little bit out of the DCI focus, and assuming many of you already know Q-in-Q, the question is, are you yet familiar with Q-in-VNI? For those who are not, I think this topic is a good opportunity to bring Q-in-VNI deployment with VXLAN EVPN for intra- and inter-VXLAN-based Fabrics and understand its added value and how one or multiple Client VLANs from the double encapsulation can be selected for further actions.
Although it’s not an unavoidable rule per-se, some readers already using Dot1Q tunneling may not necessarily fit into the following use-case. Nonetheless, I think it’s safe to say that most of Q-in-Q deployment have been used by Hosting Provider for co-location requirements for multiple Clients, hence, the choice of the Hosting Provider use-case elaborated in this article.
For many years now, Hosting Services have physically sheltered thousands of independent clients’ infrastructures within the Provider’s Data Centers. The Hosting Service Provider is responsible for supporting each and every Client’s data network in its shared network infrastructure. This must be achieved without changing any Tenant’s Layer 2 or Layer 3 parameter, and must also be done as quickly as possible. For many years, the co-location Continue reading