Networking & Security

This article is just a summarization of 2 other articles that I put on This time we will try to utilize information about QoS with simple lab.      

Access lists, prefix lists work very well in case we want to filter prefixes, but sometimes you may want to take action not against particular networks, but particular Autonomous Systems. Then AS-PATH filtering is comming forward.

Thanks to MED attribute we have influence on how adjacent eBGP router should get into our AS.It is especially helpful if we have 2 or more eBGP entrance into our AS.  Now, we will check how a single eBGP router that  receives MED attribute for the same prefix from many eBGP speakers and different AS…

ISIS is considered as a protocol only for service providers. Unfairly. Very well scalable, working with different kind of information thanks to TLV is worth to learn even if you are not going to implement its as an underlay routing protocol in MPLS environment.    

Even if we have only single point of failure at the edge it is well to have 2 upstream links. Having 2 upstream links is involved with having 2 VPN tunnels. If one of the tunnel goes down, the second takes over the tasks of the first one.      

Redistribution proces between IGP routing protocols especially with  externally redistributed networks may cause problems like routing loops or suboptimal routing. In thic article we will look closer on particular scenarios of redistribution between them.

In this lab from the scratch we will implement fully working MPLS core with Layer 3 VPN and MP-BGP vpnv4 on the provider edge routers. Also we will achieve full connectivity between customers edge routers with routing protocols. At the end we will find out how to implement “extranets” and “shared services”, thanks to which…

In this artcile we will focus on fundamental and crucial features of BGP neighborhood establishing and routes injecting into BGP processes, we also break BGP table down  for better understanding.

In this part part we will get to know what is the congestion management and queuing mechanisms based on fair queuing like Weighted Fair Queuing or Class Based Weighted Fair Queuing and how to configure them. Also how to avoid the congestion.    

In this part we will learn what is the QoS, what consists of and consists in, what are Queiuing and Scheduling. Also how to classify and mark the traffic with using of  basic configuration.      

We usually think about multicast in the context of streaming video, audio, gaming, live transmissions, but also routing protocols use multicast to send updates. Moreover, if you are going to deal with Data Center Interconnect,  you gonna come across multicast trafic. But, before we go over the lab let’s get to know what is the…

Each protocol has to calculate somehow the metric  in order to choose the best route. So we have the cost in OSPF, K-values in EIGRP, BGP doesn’t differ from them and also calculate the best route, but the metric of BGP is much more complicated.

The difference between phase 2 and 3 regarding DMVPN is slight at a first glance. In this article we will find out how to properly configure Phase 3, especially we focus on  NHRP protocol and its role. At the end we will establish full reachability between 2 spokes with utilization of EIGRP.

Sham Link feature is necessary if we want to deploy backdoor link between 2 OSPFs domains belong to the same area but split by MPLS. The issue that we will come across is a result that backdoor link will have priority over the MPLS.

We may come across on interesting issue if we get the same prefix from external BGP AS and directly via OSPF process. It may happen if we want to have another link to the destination but not neccesarily via another eBGP link. The problem that we will definetely come across on is just  another variation…