BGP
The ipTTL and ipTotalLength information elements and how they are used for network traffic analysis
Modern networks are getting increasingly complex. So many things can go wrong with them. Business can suffer, and that is something we definitely want...
SNMP evolution and version differences. SNMP security models/levels details.
Simple Network Management Protocol (SNMP) is a network application layer protocol, initially developed for network management but is now mainly used for network monitoring.
SNMP...
BGP community-based traffic engineering
BGP community attribute is a transitive optional attribute that we use for tagging (marking) a set of prefixes sharing a common property. Every BGP...
IP Transit and the Tiers of Transit Providers
The Internet consists of Internet Service Providers (ISPs) of all shapes and sizes. ISPs have two options when it comes to connecting to the...
The tightening of Internet control in Russia and potential Internet isolation tech intricacies
The Internet is for everyone, yet not everyone accepts that. In light of the news about Cogent Communications and Lumen Technologies disconnecting clients in...
BGP Anycast Best Practices & Configurations
What is Anycast?
Anycast is not a new version of IP or the latest networking technology. The RFC 1546 describing Internet anycasting for IP has...
BGP YANG Model and Configuration
YANG Data Modeling Language
Yet Another Next Generation (YANG) RFC 6020 is standard-based data modeling language for the NETCONF management protocol. YANG is used to...
The Number of the Beast or the Practical usage of the Blackhole Community
BGP blackhole filtering is a routing technique used to drop unwanted traffic. Black holes are placed in the parts of a network where unwanted...
The dark side of BGP community attributes
A while ago, RIPE Labs published the two-part article BGP Communities - A Weapon for the Internet. That may have been a bit of...
BGP peer groups, dynamic update peer groups and BGP templates
As a router gains more and more BGP neighbors, two issues arise. The first one is that with
many neighbors, whenever the router needs to...
BGP errors, BGP error codes, and BGP error handling
In this blog post we’ll be looking at BGP errors. For that, our first question should be: is there an error, or is everything...
BGP – the right tool for so many jobs
Like other very successful protocols such as HTTP and DNS, over the years BGP has been given more and more additional jobs to do....
BGP security: an overview of the RPKI framework
The Resource Public Key Infrastructure (RPKI) system is a way to couple an IP address range to an autonomous system number through cryptographic signatures,...
The 768k or Another Internet Doomsday? Here’s how to deal with the TCAM overflow at the 768k boundary.
On August 8th, 2014 some ISPs experienced a phenomenon called the “512k Day”. The global BGP routing table, which consists of the global Internet...
BGP Labeled Unicast (BGP-LU)
This blog post discusses BGP Labeled Unicast (BGP-LU) which is used in multi-regional networks to carry the label information. While the RFC3107 “Carrying Label...
Recursive Lookup in BGP
The aim of this article is to discuss the importance of Recursive Lookup in BGP. First of all we need to understand the purpose...
Accumulated IGP and BGP
RFC 7311 defines an optional non-transitive BGP attribute called the Accumulated IGP Metric Attribute (AIGP).
As we know, IGP stands for Interior Gateway Protocol...
QoS Policy and its propagation via BGP (QPPB)
Quality of Service (QoS) refers to a collection of technologies that networking devices use to apply different treatment to packets as they pass through...
BGP Conditional Route Injection
We have recently posted the BGP Route Aggregation eBook that discusses the benefits of route aggregation and explains the various optional parameters associated with...
BGP Route Dampening: obsolete or still used in the industry?
The unstable route whose availability alters repeatedly is called a flap. When flaps occur, an excessive number of BGP UPDATE messages are sent to...
BGP Attribute Filtering and Error Handling
The BGP Attribute Filter feature enables BGP speakers to take a certain action based on the presence of a specified path attribute inside the...
BGP Optimal Route Reflection as an alternative to BGP Add Path
Full iBGP Mesh and Route Reflection
To avoid loops in a Full iBGP Mesh, BGP routers are only allowed to learn prefixes over iBGP from...
Network Address Translation (NAT) and BGP Explained
Network Address Translation (NAT) was originally described in RFC 1631. Although initially presented as a short term solution for preventing the IPv4 addresses depletion,...
Advertising Multiple Paths in BGP (BGP-Addpath)
The BGP advertisement of a prefix with new attributes replaces the previous announcement of that prefix. This behavior is known as an Implicit Withdraw,...
BGP and Traffic Engineering Mechanisms for WISPs
In this blog post, we will take a look at Kevin Myers's presentation where he discusses deployment of both OSPF and BGP routing protocols...
Bit Indexed Explicit Replication and the BGP Extensions for BIER
In this article we’ll take a look at the architecture for multicast forwarding called the Bit Indexed Explicit Replication or simply BIER. However, we’ll...
BGP/MPLS Layer 3 VPNs Practical Configuration
In our previous blog article we’ve discussed the benefits and the fundamental principles of BGP/MPLS L3 VPNs. We have covered the definition of the...
BGP / MPLS Layer 3 VPNs
What is VPN?
Virtual Private Networks (VPN) are designed to provide users with the private networks capabilities over a shared infrastructure. They connect remote sites...
Internet of Things and BGP
The Internet of Things (IoT) attracts huge public attention nowadays. It is a network of interconnected physical devices (things) which sense and interact with...
BGP and Cryptocurrencies
What is Cryptocurrency?
Cryptocurrency is a digital asset that works as a medium of exchange. It uses cryptography to secure transactions and to control the...
BGP in Large-Scale Data Centers
Large-scale data centers (DCs) connect hundreds of thousands or even more servers, having millions of users. Generally, every DC runs two kinds of applications....
BGP over GRE Tunnel
In this blog post we are going to explain how Generic Routing Encapsulation (GRE) tunnel might be used in a situation when the Border...
What BGP Looking Glass servers are and how network administrators use them.
Whether you are an experienced network administrator or you have just started to learn Border Gateway Protocol (BGP), Looking Glass (LG) is definitely a...
Noction bets on BGP FlowSpec
While networks are agnostic to the content of the serviced packets, end users have a very good understanding of what traffic they have and...
BGP and asymmetric routing
What is Asymmetric Routing?
Asymmetric routing is the situation where packets from A to B follow a different path than packets from B to A....
Migrating to BGP
Here on the Noction blog we've covered many aspects of using BGP to connect your network to the internet. However, often implementing BGP isn't...
BGP and equal-cost multipath (ECMP)
One given in the network world is that bandwidth will increase. So that Gigabit Ethernet link that provided bandwidth to spare a year ago...
Lesser-known BGP path attributes
The past few weeks we've discussed the main BGP path attributes: the next hop, the AS path, the MED. We also covered the community...
Optimizing network performance for online gaming
In many online games, very good network performance is a prerequisite for satisfactory gameplay. However, there are many kinds of games, and their networking...
BGP security: announcing prefixes without authorization
In our last post, we looked at protecting the TCP session that carries BGP information between two routers, mainly against spoofed TCP resets. However,...
BGP Security: the MD5 password and GTSM
Back in the late 1980s and the early 1990s when BGP was developed, security was still an afterthought for protocols used on the internet....
Do route optimizers cause fake routes?
Yesterday, an incident occurred where an Autonomous System (AS) advertised more than 7,000 prefixes that belong to other networks. These are "more specific" prefixes—subsets...
What should your peering policy look like?
As discussed in earlier posts, as networks grow larger it starts making sense to exchange traffic with other networks directly (peering) rather than pay...
IPv4 BGP vs IPv6 BGP
BGP is older than IPv6. Even BGP-4, the version we still use today, predates IPv6: the first BGP-4 RFC (RFC 1654) was published in...
The top 4 causes of network downtime
Business people often believe that in order to have a reliable system, you need reliable components. Using reliable components to build your network certainly...
BGP and OSPF. How do they interact.
In some ways, BGP is nice and simple. For instance, there's only one BGP: BGP version 4. Many network professionals have been asking the...
Understanding BGP Communities
After reading the title of this article you may be thinking of small neighborhoods in the world's most-connected cities where BGP-minded people live together,...
Filtering your BGP updates
One thing we all learn quickly after getting started with BGP is that if left to its own devices, the protocol will happily propagate...
Why BGP is not enough?
It’s common knowledge that Border Gateway Protocol has no ability to make performance-based routing decisions and often routes traffic through paths that are congested...
Route Reflectors – an alternative to full-mesh iBGP configuration
The typical fully-meshed iBGP configuration of routers can become very difficult to manage in large networks. Because of the increasing numbers of iBGP sessions...
Routing anomalies – their origins and how do they affect end users
Nowadays, the Internet is made-up of more than 45,000 active Autonomous Systems (ASes), each with a different complexity level and specific configurations. To accomplish...
BGP-based inter-domain traffic engineering: important considerations
Inter-domain traffic engineering aims to optimize traffic performance, originating and terminating in different administrative domains. At the moment, Autonomous Systems exchange traffic via exterior...
Deploying BGP for redundant IP connectivity
All organizations that depend on Internet for sales revenue or business continuity require internet redundancy. Downtime lowers productivity, yields losses and painfully affects the...
Is BGP multi-homing enough for WAN network performance?
BGP multihoming has become as necessary to the networks connected to Internet, as the use of redundant power sources or multiple data centers. No...