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This post will describe some of the crypto design considerations for DMVPN.
DMVPN Overview and Crypto Overhead
First let’s have a quick recap of what Dynamic Multipoint VPN (DMVPN) is. DMVPN is an overlay technology where multi point GRE tunnels are used to form an overlay where a routing protocol will run across the overlay. DMVPN is a hub and spoke technology where the DMVPN hub acts as a centralized control plane. DMVPN uses Next Hop Resolution Protocol (NHRP) to register the IP addresses of the spokes with the hub. When a router looks in its routing table, the next-hop will be the IP address of the tunnel, not the real outside IP which must be used for the GRE encapsulation. To find the outside IP of the spoke, NHRP is used to resolve the next-hop to the real outside IP.
DMVPN runs over public transport. This means that it’s possible to snoop the traffic while in transit. To prevent this from happening, DMVPN is often combined with IPSec to encrypt the packets. IPSec can run in two modes, transport mode and tunnel mode. In transport mode, the original IP header is not encrypted and there is no additional IP Continue reading
We had some great vendor presentations at Networking Field Day 11 and in the face of some pretty stiff competition, Citrix won my inaugural Best surprise
award, which I have just invented.
It’s not that the Citrix NetScaler Application Delivery Controller (ADC) is a particularly unique product; after all, I could as easily implement load balancing with the open source HAProxy, and there are impressive ADC hardware vendors in the commercial space, including the ubiquitously expensive F5 Networks and disruptive challenger A10 Networks. What grabbed my interest me however were the performance statistics of the NetScaler appliances, and specifically the process through which the performance was achieved by the Citrix engineering team.
If I might side track for a moment, at Networking Field Day 10, Intel discussed their DPDK (Data Plane Development Kit) designed to optimize soft-switched packet performance on their CPUs. Intel had noted that the performance of Open vSwitch (OVS) was nowhere near the native ability of the CPU, and consequently they invested time analyzing in scary detail exactly how packets flowed in order to find out where the bottlenecks were, and to see whether those could be eliminated or optimized in Continue reading
IT pros looking to expand their horizons or learn new skills can benefit from these professional groups.
ARM's 64-bit push is underway, but will the data center be interested?
Bonded channels make sense in certain types of WLAN deployments, but not others.
The new WiFi HaLow standard may sacrifice some speed, but the benefits are worth it.
A while ago someone posted a link to an article that links to LinkedIn’s blog post describing their switch-building efforts to the LinkedIn SDN group (how’s that for a circular reference?), and a consultant from Brocade felt compelled to share his wisdom with the world. Unfortunately he got most of the facts wrong.
Read more ...Far far away, behind the word mountains, far from the countries Vokalia and Consonantia, there live the blind texts. Separated they live in Bookmarksgrove right at the coast of the Semantics, a large language ocean. A small river named Duden flows by their place and supplies it with the necessary regelialia. It is a paradisematic country, in which roasted parts of sentences fly into your mouth.
Even the all-powerful Pointing has no control about the blind texts it is an almost unorthographic life One day however a small line of blind text by the name of Lorem Ipsum decided to leave for the far World of Grammar. The Big Oxmox advised her not to do so, because there were thousands of bad Commas, wild Question Marks and devious Semikoli, but the Little Blind Text didn’t listen.
She packed her seven versalia, put her initial into the belt and made herself on the way. When she reached the first hills of the Italic Mountains, she had a last view back on the skyline of her hometown Bookmarksgrove, the headline of Alphabet Village and the subline of her own road, the Line Lane. Pityful a rethoric question ran over her cheek, then Continue reading
Far far away, behind the word mountains, far from the countries Vokalia and Consonantia, there live the blind texts. Separated they live in Bookmarksgrove right at the coast of the Semantics, a large language ocean. A small river named Duden flows by their place and supplies it with the necessary regelialia. It is a paradisematic country, in which roasted parts of sentences fly into your mouth.
Even the all-powerful Pointing has no control about the blind texts it is an almost unorthographic life One day however a small line of blind text by the name of Lorem Ipsum decided to leave for the far World of Grammar. The Big Oxmox advised her not to do so, because there were thousands of bad Commas, wild Question Marks and devious Semikoli, but the Little Blind Text didn’t listen.
She packed her seven versalia, put her initial into the belt and made herself on the way. When she reached the first hills of the Italic Mountains, she had a last view back on the skyline of her hometown Bookmarksgrove, the headline of Alphabet Village and the subline of her own road, the Line Lane. Pityful a rethoric question ran over her cheek, then Continue reading