What is 6PE?

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6PE is one of the efficient solutions for interconnecting IPv6 islands over an IPv4-only MPLS cloud without needing to drastically change the core network design by having all your Core routers dual-stacked 6PE does not use manual standard tunnels, it provides an alternative where all tunnels are established dynamically eliminating the need to configure and maintain tunnels. The approach requires that the edge routers connected to IPv6 islands be Dual Stack Multiprotocol-BGP-speaking routers. while the core routers can only run IPv4 MPLS Configuring 6PE is has a lot of similarities with configuring  IPv4 VPNs as both use MP-BGP to distribute non-IPv4 reachability …

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CCIE SPv4.1 Blueprint Resources

The CCIE SP SME team has put a comprehensive list of study resources for the new CCIE SP4.1 blueprint. The complied list is in a spreadsheet designed to help you quickly find what you are looking for by organizing the content according to the exam topics. This is a very good resource for finding good information regardless of the exam. You can download the spreadsheet @ CCIE_SP_version4.1_prep_resources.xlsx. Find out more information at Cisco Learning Network.

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TCP Protocol: TCP 3-way handshaking #2

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In the last post, we have explained the TCP 3-way handshaking from an abstract point of view, and knew that one of the main functions of this handshaking is to exchange and synchronize some parameters for the TCP connection endpoints to facilitate its job. We also knew that two of the main parameters that the end-points exchange in the TCP 3-way handshaking are the SEQUENCE and ACK numbers. Today, we will continue the 3-way handshaking process in more details. Above is a TCP capture file which I downloaded from “Wireshark” wiki page that shows 3 packets in sequence between two end-hosts. From …

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TCP Protocol: Three-way Handshake

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We all know by now that the basic function of the TCP protocol is to send a stream of bytes that has no shape or fixed size over a network reliably to a receiver. We all also know that reliable delivery involves building a connection between two end-hosts, and this will be the first step that the TCP stack do to exchange data. Above figure, has a host on a side and a server on the other. Host needs to get/download a file from the server via FTP protocol which is dependent on TCP. The Host will start off by allocating …

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TCP Protocol: The Overview – Part1

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One of the most important layers we – as network engineers – hate and avoid in the OSI reference model is the transport layer with its popular and dominant protocol; TCP. Most of network engineers abandoned diving into TCP protocol because they consider it a host-to-host communication protocol that usually works without a problem. End systems either Windows or Linux gets installed with their own version of TCP stack with some pre-configured values that usually don’t break, so why would we bother ourselves learning about one of the most important protocol in the TCP/IP stack! The irony here is that, System Engineers, Application …

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JUNOS Disable vs Deactivate interfaces

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Confusing between disabling and deactivating interfaces on JUNOS is a common mistake that leads to all sorts of problems during implementing changes on live network boxes. Let’s look and clarify the differences quickly. Disabling an interface: Disabling an interface in JUNOS is equivlaent to interface shutdown in Cisco, it is going to take the interface administratevly down completely without impacting the configuration on that interface as you can see below. --- Interface in UP UP state triton@neptune> show interfaces ge-0/0/0 terse Interface               Admin Link Proto    Local                 Remote ge-0/0/0                up    up ge-0/0/0.0              up    up   inet     172.18.0.1/24 -- Disable the interface triton@neptune> …

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