BGP Interview Questions

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.

Which of the below option is the reason to run IBGP? (Choose Two)

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

BGP Labeled Unicast Interoperability Challenges

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:

Read more …

BGP Labeled Unicast Interoperability Challenges

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:

Read more …

AMD grabs DPU maker Pensando for a cool $1.9B

Advanced Micro Devices took a big step toward competing in data-center networking with its announced agreement to acquire Pensando for approximately $1.9 billion.   AMD wants the DPU-based architecture and technology Pensando is developing that includes intelligent, programmable software to support software-defined cloud, compute, networking, storage, and security services that could be rolled out quickly in edge, colocation, or service-provider networks.What is SDN and where it’s going “There are a wide range of use cases—such as 5G and IoT—that need to support lots of low latency traffic,” Soni Jiandani, Pensando co-founder and chief business office told Network World last November:“We’ve taken a ground-up approach to giving enterprise customers a fully programmable system with the ability to support multiple infrastructure services without dedicated CPUs.”To read this article in full, please click here

AMD grabs DPU maker Pensando for a cool $1.9B

Advanced Micro Devices took a big step toward competing in data-center networking with its announced agreement to acquire Pensando for approximately $1.9 billion.   AMD wants the DPU-based architecture and technology Pensando is developing that includes intelligent, programmable software to support software-defined cloud, compute, networking, storage, and security services that could be rolled out quickly in edge, colocation, or service-provider networks.What is SDN and where it’s going “There are a wide range of use cases—such as 5G and IoT—that need to support lots of low latency traffic,” Soni Jiandani, Pensando co-founder and chief business office told Network World last November:“We’ve taken a ground-up approach to giving enterprise customers a fully programmable system with the ability to support multiple infrastructure services without dedicated CPUs.”To read this article in full, please click here

IBM z16: A mainframe designed for AI, hybrid cloud, security and open source

Today’s announcement of IBM’s new z16 mainframes promises a system that caters to enterprise needs that include support for AI, security, hybrid cloud, and open source efforts well into the future.The new, more powerful and feature-rich Big Iron boasts an AI accelerator built onto its core Telum processor that can do 300 billion deep-learning inferences per day with one millisecond latency and includes what IBM calls a quantum-safe system to protect organizations from anticipated quantum-based security threats. [Get regularly scheduled insights by signing up for Network World newsletters.]To read this article in full, please click here

IBM z16: A mainframe designed for AI, hybrid cloud, security and open source

Today’s announcement of IBM’s new z16 mainframes promises a system that caters to enterprise needs that include support for AI, security, hybrid cloud, and open source efforts well into the future.The new, more powerful and feature-rich Big Iron boasts an AI accelerator built onto its core Telum processor that can do 300 billion deep-learning inferences per day with one millisecond latency and includes what IBM calls a quantum-safe system to protect organizations from anticipated quantum-based security threats. [Get regularly scheduled insights by signing up for Network World newsletters.]To read this article in full, please click here

IBM’s game-changing mainframe moments

With the advent of the latest generation of IBM mainframes – the z16 – Big Blue is furthering one of the most successful technology systems the IT world has known.  Here are a few key moments in the history of the Big Iron:IBM 360 In 1964 IBM began what many would consider the first true series of mainframes, the IBM 360. At the time IBM said its central processors included 19 combinations of graduated speed and memory capacity. The system also included more than 40 types of peripheral equipment  for entering, storing, and retrieving information. Built-in communications capability made the System/360 available to remote terminals, regardless of distance.To read this article in full, please click here

IBM’s game-changing mainframe moments

With the advent of the latest generation of IBM mainframes – the z16 – Big Blue is furthering one of the most successful technology systems the IT world has known.  Here are a few key moments in the history of the Big Iron:IBM 360 In 1964 IBM began what many would consider the first true series of mainframes, the IBM 360. At the time IBM said its central processors included 19 combinations of graduated speed and memory capacity. The system also included more than 40 types of peripheral equipment  for entering, storing, and retrieving information. Built-in communications capability made the System/360 available to remote terminals, regardless of distance.To read this article in full, please click here

IBM’s game-changing mainframe moments

With the advent of the latest generation of IBM mainframes – the z16 – Big Blue is furthering one of the most successful technology systems the IT world has known.  Here are a few key moments in the history of the Big Iron:IBM 360 In 1964 IBM began what many would consider the first true series of mainframes, the IBM 360. At the time IBM said its central processors included 19 combinations of graduated speed and memory capacity. The system also included more than 40 types of peripheral equipment  for entering, storing, and retrieving information. Built-in communications capability made the System/360 available to remote terminals, regardless of distance.To read this article in full, please click here

Device Management From The Ground Up: Part 5 – External File Management

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, […]

The post Device Management From The Ground Up: Part 5 – External File Management appeared first on Packet Pushers.

OSPF FAQ – Frequently Asked Questions

In this post, some of the frequently asked OSPF questions will be answered. Some of the answers will be from a design point of view and we will try to provide enough justification for the answer. Questions are selected randomly, not based on the order of importance.

How many routers should be placed in one OSPF area?

We don’t give any numerical number as an answer to this question. Depending on the number of routers, links, prefixes, and the topology of the network also depends on the hardware capabilities and the performance of the routers, the number change from Network to network. In some networks, you can place only a couple of hundreds, and in some networks, you can place thousands of Routers in a single OSPF Area.

What command would you use to only see the OSPF routes in the routing table?

On Cisco devices, sh ip route ospf is used to see only the OSPF routes in the routing table.

What will an OSPF router prefer to use first as a router-id?

The first preference for an OSPF router ID is an explicitly configured 32-bit address. This address is not included in the routing table and is not Continue reading

BGP Policies (Part 4)

At the most basic level, there are only three BGP policies: pushing traffic through a specific exit point; pulling traffic through a specific entry point; preventing a remote AS (more than one AS hop away) from transiting your AS to reach a specific destination. In this series I’m going to discuss different reasons for these kinds of policies, and different ways to implement them in interdomain BGP.

In this post, I’ll cover the first of a few ways to give surrounding autonomous systems a hint about where traffic should enter a network. Note this is one of the most vexing problems in BGP policy, so there will be a lot of notes across the next several posts about why some solutions don’t work all that well, or when they will and won’t work.

There are at least three reasons an operator may want to control the point at which traffic enters their network, including:

  • Controlling the inbound load on each link. It might be important to balance inbound and outbound load to maintain settlement-free peering, or to equally use all available inbound bandwidth, or to ensure the quality of experience is not impacted by overusing a single link.
  • Accounting for Continue reading

Fortinet tightens integration of enterprise security, networking controls

Fortinet has made available a new release of its core FortiOS software that includes features the vendor says will help enterprises more tightly meld security and networking controls.FortiOS 7.2, has 300 new features including AI support to help stop network threats more quickly, sandboxing to help fight ransomware threats, and improved SD-WAN, branch, and edge orchestration.How to choose an edge gateway FortiOS is the vendor’s operating system for the FortiGate family of hardware and virtual components. FortiOS implements Fortinet Security Fabric and includes network security such as firewalling, access control, and authentication in addition to SD-WAN, switching, and wireless services. To read this article in full, please click here

Fortinet tightens integration of enterprise security, networking controls

Fortinet has made available a new release of its core FortiOS software that includes features the vendor says will help enterprises more tightly meld security and networking controls.FortiOS 7.2, has 300 new features including AI support to help stop network threats more quickly, sandboxing to help fight ransomware threats, and improved SD-WAN, branch, and edge orchestration.How to choose an edge gateway FortiOS is the vendor’s operating system for the FortiGate family of hardware and virtual components. FortiOS implements Fortinet Security Fabric and includes network security such as firewalling, access control, and authentication in addition to SD-WAN, switching, and wireless services. To read this article in full, please click here

Fortinet tightens integration of enterprise security, networking controls

Fortinet has made available a new release of its core FortiOS software that includes features the vendor says will help enterprises more tightly meld security and networking controls.FortiOS 7.2, has 300 new features including AI support to help stop network threats more quickly, sandboxing to help fight ransomware threats, and improved SD-WAN, branch, and edge orchestration.How to choose an edge gateway FortiOS is the vendor’s operating system for the FortiGate family of hardware and virtual components. FortiOS implements Fortinet Security Fabric and includes network security such as firewalling, access control, and authentication in addition to SD-WAN, switching, and wireless services. To read this article in full, please click here

Real-time flow telemetry for routers

The last few years have seen leading router vendors add support for sFlow monitoring technology that has long been the industry standard for switch monitoring. Router implementations of sFlow include:
  • Arista 7020R Series Routers, 7280R Series Routers, 7500R Series Routers, 7800R3 Series Routers
  • Cisco 8000 Series Routers, ASR 9000 Series Routers, NCS 5500 Series Routers
  • Juniper ACX Series Routers, MX Series Routers, PTX Series Routers
  • Huawei NetEngine 8000 Series Routers
Broad support of sFlow in both switching and routing platforms ensures comprehensive end-to-end monitoring of traffic, see sFlow.org Network Equipment for a list of vendors and products.
Note: Most routers also support Cisco Netflow/IPFIX. Rapidly detecting large flows, sFlow vs. NetFlow/IPFIX describes why you should choose sFlow if you are interested in real-time monitoring and control applications.
DDoS mitigation is a popular use case for sFlow telemetry in routers. The combination of sFlow for real-time DDoS detection with BGP RTBH / Flowspec mitigation on routing platforms makes for a compelling solution.
DDoS protection quickstart guide describes how to deploy sFlow along with BGP RTBH/Flowspec to automatically detect and mitigate DDoS flood attacks. The use of sFlow provides sub-second visibility into network traffic during the periods of high packet loss Continue reading

Internet disruptions overview for Q1 2022

Internet disruptions overview for Q1 2022
Internet disruptions overview for Q1 2022

Cloudflare operates in more than 250 cities in over 100 countries, where we interconnect with over 10,000 network providers in order to provide a broad range of services to millions of customers. The breadth of both our network and our customer base provides us with a unique perspective on Internet resilience, enabling us to observe the impact of Internet disruptions. In many cases, these disruptions can be attributed to a physical event, while in other cases, they are due to an intentional government-directed shutdown. In this post, we review selected Internet disruptions observed by Cloudflare during the first quarter of 2022, supported by traffic graphs from Cloudflare Radar and other internal Cloudflare tools, and grouped by associated cause.

Plate tectonics

Internet outages caused by “earth movers” are more frequently caused by errant backhoes. However, two Internet disruptions in the first quarter were caused by more significant earth movement — a volcanic eruption and an earthquake.

The first impacted connectivity on the island nation of Tonga, when the Hunga Tonga–Hunga Ha'apai volcanic eruption damaged the submarine cable connecting Tonga to Fiji, resulting in a 38 day Internet outage. After the January 14 eruption, only minimal Internet traffic (via satellite Continue reading

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