In this post, we will compare EIGRP and OSPF. We will look at some of the important aspects when we compare EIGRP vs OSPF. From scalability, standardization, working on different topologies and many aspects will be compared in this most detailed comparison blog post on the Internet.
We prepared the above comparison chart for EIGRP vs OSPF comparison. We will look at some of those important Comparison criteria from a design point of view.
OSPF supports two layers of Hiearchicy. OSPF Backbone areas and OSPF Non-backbone areas. EIGRP on the other side supports as many as you want. You can summarize EIGRP prefixes at every hop. This capability provides a scale advantage to EIGRP. In EIGRP, we don’t need an ABR node for summarization for example.
The full mesh may require a lot of logical connections, OSPF with Mesh-group feature can scale but it can be a scaling problem for the EIGRP networks. If we think that in real-life networks, EIGRP is usually used in Hub and Spoke topologies most of the time, expecting EIGRP to run on Full-mesh topologies is not Continue reading
In this post, we will compare BGP and OSPF. We will look at some of the important aspects when we compare BGP vs OSPF. Although OSPF is used as an IGP and BGP is used mainly as an External routing protocol, we will compare from many different design aspects. Also, BGP can be used as an Internal IGP protocol as well and we will take that into consideration as well.
We prepared the above comparison chart for BGP vs OSPF comparison. We will look at some of those important Comparison criteria from a design point of view.
One of the biggest reasons we choose BGP, not OSPF is Scalability. BGP is used as a Global Internet routing protocol and as of 2022, the Global routing table size for IPv4 unicast prefixes is around 900 000. So almost a million prefixes we carry over BGP on the Internet.
So, proven scalability for BGP we can say. OSPF usually can carry only a couple of thousands of prefixes, this is one of the reasons, OSPF is used as an Internal dynamic routing protocol, not over the Internet.
At Cloudflare, we’re used to being the fastest in the world. However, for approximately 30 minutes last December, Cloudflare was slow. Between 20:10 and 20:40 UTC on December 16, web requests served by Cloudflare were artificially delayed by up to five seconds before being processed. This post tells the story of how a missing shell option called “pipefail” slowed Cloudflare down.
Before we can tell this story, we need to introduce you to some of its characters.
Cloudflare’s Front Line protects millions of users from some of the largest attacks ever recorded. This protection is orchestrated by a sidecar service called dosd
, which analyzes traffic and looks for attacks. When dosd
detects an attack, it provides Front Line with a list of attack fingerprints that describe how Front Line can match and block the attack traffic.
Instances of dosd
run on every Cloudflare server, and they communicate with each other using a peer-to-peer mesh to identify malicious traffic patterns. This decentralized design allows dosd
to perform analysis with much higher fidelity than is possible with a centralized system, but its scale also imposes some strict performance requirements. To meet these requirements, we need to provide dosd
with very Continue reading
BGP Weight Attribute is used in Cisco routers. In this post, with the below topology, we will look at why the BGP weight attribute is used, why it BGP weight shouldn’t be used, advantages and disadvantages of the BGP weight attribute.
Let’s first define what is BGP Weight attribute. BGP selects the best path based on the BGP path attributes. Weight is considered a very important tie-breaker in BGP’s best-path selection.
When there are two paths to any BGP destination prefix, the BGP Weight attribute is compared before BGP Local Preference and many other BGP Path attributes.
Since this is not BGP’s best path selection post, and assuming you already know the process, please note, Weight attribute is compared before even BGP Local Preference.
But, let’s have a look at the below topology to understand it better.
In the above topology, we want to use the left path for the prefixes in AS1, thus we have a higher BGP Local preference value.
As the BGP Local preference value is exchanged internally between all IBGP neighbors, both left and right routers in AS65000, use the left exit point, which is Local Pref 100 to reach the Continue reading
BGP Interview questions and answers are shared here. In this post, we will look at some of the important BGP questions that are asked in the Interviews and some of the certification exams. You can consider this as a BGP Quiz and test your BGP knowledge.
A. It is used for the reachability between PE devices in the MPLS network
B. It is used to carry EBGP prefixes inside an Autonomous System
C. It is used with Route Reflectors for the scalability reason in large scale networks
D. It is used to prevent failures outside your network from impacting your internal network operation
Answer: One of the correct answers to this question is to carry EBGP prefixes inside an Autonomous system. IGP is used for the reachability between PE devices in an MPLS network. Option C is valid but not the correct answer, because; the question is asking about the reasons, not the best practices.
Option D is one of the correct answers as well because, with IBGP, the internal network is protected from outside failures by separating the local failure domains.
That’s why; the answers to Continue reading
Jeff Tantsura left me tantalizing hint after reading the BGP Labeled Unicast on Cisco IOS blog post:
Read carefully “Relationship between SAFI-4 and SAFI-1 Routes” section in RFC 8277
The start of that section doesn’t look promising (and it gets worse):
It is possible that a BGP speaker will receive both a SAFI-11 route for prefix P and a SAFI-42 route for prefix P. Different implementations treat this situation in different ways.
Now for the details:
Jeff Tantsura left me tantalizing hint after reading the BGP Labeled Unicast on Cisco IOS blog post:
Read carefully “Relationship between SAFI-4 and SAFI-1 Routes” section in RFC 8277
The start of that section doesn’t look promising (and it gets worse):
It is possible that a BGP speaker will receive both a SAFI-11 route for prefix P and a SAFI-42 route for prefix P. Different implementations treat this situation in different ways.
Now for the details:
Today on the Tech Bytes podcast we’re talking about disaggregated optical networks and what they mean for both customers and carriers when it comes to issues such as service delivery and cost. Our sponsor is Arelion.
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This post originally appeared on the Packet Pushers’ Ignition site on April 16, 2021. We’ve explored the various filesystems on Cisco devices, but you may have wondered how we get new files onto our devices. How do we backup files from our devices? This article explains copying files to and from a Cisco device. Additionally, […]
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