Do you ever find yourself in a conversation with someone where you attempt to explain a concept in detail and you realize that you don't know that concept at the level of detail that you thought you did? That happened to me recently. I thought I had a better handle on TRILL and FabricPath than I really did. Since I retain things far better when I write them down, I'm going to blog the differences between TRILL and FabricPath when it comes to address learning and what role the control plane plays in building the network topology
Serverfarms allow probes to be associated with them when configured.
Any rserver in the serverfarm configuration will inherit probes from the serverfarm config.
Default probe behaviour is to use OR logic. A single probe failure will cause the rserver to be marked as down.
AND logic for probes can be applied using the fail-on-all command. This means all probes must fail for the serverfarm to be marked as down.
How does the internet work - We know what is networking
Next project was one of my first networking Science articles. It is a short look at latest achievements from some of the biggest networking scientists today with some short comments from my mentor and me. The work was presented at 19. International scientific conference of International Federation of Communication Associations. International scientific conference “DIT 2012″ accepts […]
How does the internet work - We know what is networking
If you work in networking sooner or later there will be a situation where someone will bring you a device that you must connect to your network that was used somewhere else before. That can be something like switch, Fiber channel switch, some security appliance, different controllers etc. In that case this device will often […]
As of 10:27 UTC this morning the majority of the Internet in Syria is no longer connected to the rest of the world and can be considered as offline. Syria has only one major provider, AS29256 The Syrian Telecommunications Establishment. This provider is government owned and originates 56 out of 62 Syrian prefixes.
This morning between 10:26 and 10:27 all routes originated by AS29256 (The Syrian Telecommunications Establishment) were withdrawn and became unreachable.
The only Syrian prefixes left in the routing table are 5 prefixes originated by TATA, AS6453. These are the prefixes that are still reachable via TATA:
216.6.0.0/23, 63.243.163.0/24, 116.0.72.0/22, 66.198.39.0/24, 66.198.41.0/24
What happened?
We have no official confirmation about what happened, but similar events in the past [Syria, Egypt] were all government ordered. Because the primary telecom provider is state controlled in Syria, an outage like this is relatively easy to implement by ordering the primary telecom provider to shutdown the external links or BGP sessions with the external providers. External providers that provide services to Syria are:
AS9121 Turk Telecom
AS6762 telecom Italia
AS3491 PCCW Global
AS6453 Tata
Not the first outage
How does the internet work - We know what is networking
Session Announcement Protocol as an experimental protocol designed for the purpose of multicasting a session’s information. IETF issued it as RFC 2974. SDP (Session Description Protocol) is being used by SAP as real-time transport protocol’s session depiction arrangement. With SAP use, correspondent can transmit SDP descriptions from time to time to an acknowledged multicast address […]
How does the internet work - We know what is networking
This is a movie based on a true story. Is the issue you will have sooner or later if you are into networking and managing devices? Perhaps you will manage to upgrade hundreds of devices before you will see this happening but maybe it will be one of the first devices in production environment to […]
Recovery From Corrupt or Missing Software Image on Cisco device
