We kick off the CCNA series from the beginning. Operation of IP data networks is weighted as 5% in the CCNA RS blueprint. The first topic is:
1.1 Recognize the purpose and functions of various network devices such as routers, switches, bridges and hubs
Router
A router is a device that routes between different networks, meaning that it looks at the IP header and more specifically the destination IP of a packet to do forwarding. It uses a routing table which is populated by static routes and routes from dynamic protocols such as RIP, EIGRP, OSPF, ISIS and BGP. These routes are inserted into the Routing Information Base (RIB). The routes from different sources compete against each other and the best route gets inserted into the RIB. To define how trustworthy a route is, there is a metric called Administrative Distance (AD). These are some of the common AD values:
0 Connected route 1 Static route 20 External BGP 90 EIGRP 110 OSPF 115 ISIS 120 RIP 200 Internal BGP 255 Don't install
If a value of 255 is used, the route will not installed in the RIB as the route is deemed not trustworthy at all.
The goal Continue reading
Learn how providers can lay the groundwork for networks with ultra-high bandwidth, ultra-low latency, context-based control, network slices, and distributed deployment.
I run collectd stats on many of my servers and one thing I enable on some (but not all) of the
How VMware's own value got virtualized.
What a week. Some tech conferences I like, and others I love. Falling solidly in my "love" category, the Amazon team pulled off another great event with re:Invent 2015. Of course, the AWS product folks didn’t disappoint, either. (And neither did surprise re:Play party guest Zedd.)
We welcomed many hundreds of visitors to our booth during the three days. Over 200 shirts, many more Ansibulls, and every single sticker, luggage tag, and business card were gobbled up by excited Ansible users and Tower customers.
Perhaps the most entertaining part was to learn what people had to say:
Network Break 57 delves into Dell and EMC and looks at upheavals affecting Juniper, Cisco, and AT&T. We also run from a new Verizon zombie tracking cookie, and opine on the rest of the week's tech news.
The post Network Break 57: Vendor Upheaval, Zombie Cookies Bite appeared first on Packet Pushers.
For a long time now stateless services have been the royal road to scalability. Nearly every treatise on scalability declares statelessness as the best practices approved method for building scalable systems. A stateless architecture is easy to scale horizontally and only requires simple round-robin load balancing.
What’s not to love? Perhaps the increased latency from the roundtrips to the database. Or maybe the complexity of the caching layer required to hide database latency problems. Or even the troublesome consistency issues.
But what of stateful services? Isn’t preserving identity by shipping functions to data instead of shipping data to functions a better approach? It often is, but we don’t hear much about how to build stateful services. In fact, do a search and there’s very little in the way of a systematic approach to building stateful services. Wikipedia doesn’t even have an entry for stateful service.
Caitie McCaffrey, Tech Lead for Observability at Twitter, is fixing all that with a refreshing talk she gave at the Strange Loop conference on Building Scalable Stateful Services (slides).
Refreshing because I’ve never quite heard of building stateful services in the way Caitie talks about building them. You’ll recognize most of the Continue reading
The post Worth Reading: Hybrid Infrastructure appeared first on 'net work.
This vendor-written tech primer has been edited by Network World to eliminate product promotion, but readers should note it will likely favor the submitter’s approach.
From Target to Ashley Madison, we’ve witnessed how interconnections with third-party vendors can turn an elastic environment -- where devices, services and apps are routinely engaging and disengaging -- into a precarious space filled with backdoors for a hacker to infiltrate an enterprise’s network. Here are the top five threats related to working with 3rd parties:
Threat #1 - Shared Credentials. This is one of the most dangerous authentication practices we encounter in large organizations. Imagine a unique service, not used very frequently, requiring some form of credential-based authentication. Over time, the users of this service changes, and for convenience considerations, a single credential is often used. The service is now accessed from multiple locations, different devices and for different purposes. It takes just one clumsy user to fall victim to one {fill in the credential harvesting technique of your choice}, to compromise this service and any following user of that service.
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The 2015 Layer 123 SDN & OpenFlow World Congress will be available live on Monday October 13th and Tuesday October 14th. Watch the live stream of the event for free on SDxCentral.