bgp interview questions Archives

BGP Interview Questions and Answers:

May 17, 2023March 25, 2023 by Aakriti

1. What is BGP in CCNA?

Border Gateway Protocol (BGP) is the routing protocol of the Internet. Meaning it chooses the best path for communication to happen between two or more routers. Some of the distinguishing features of BGP include:

It is the biggest routing protocol in the world.
It manages the trusted and untrusted routes.
It enables routing through autonomous systems instead of routers.
It is the slowest routing protocol in the world.
It is primarily used for service providers.
It can also be used for enterprise customers.

Now that you are completely aware of BGP, we can move ahead. Also, this works as the very first interview question.

It is time to graze over some other tricky BGP interview questions and answers.

2. How does BGP work?

BGP connection between two routers is called a peering session. This simply means that the two routers have established a communication channel. This would allow the exchange of information.

Once peering occurs, here is how BGP works step by step:

It will look for routes among all the External BGP routers it has in the neighborhood.
It will also look for the Internal BGP routers it has in its own Autonomous System (AS).
After applying filters, it picks up the best path.
It installs it in the routing table (RIB).
Then, the best route is sent to the external BGP neighbors.

This further leads to several sub-processes. These are:

BGP ‘in’ Process:

It receives path information from peers.
The results of the best BGP path selection are placed in the BGP table.
The best path is then ‘flagged’.

BGP ‘out’ Process:

Share the best path information to peers.

Its very common asked question in BGP interview questions

3. What does BGP mean in networking?

BGP makes the Internet work. The Internet is nothing with BGP.

BGP allows every Autonomous System (AS) to discover routes to other ASs. It is only the responsibility of BGP to filter and change the routes. In short, BGP lets you apply a wide range of policies to control the traffic. It can change the path of traffic.

As we know, the Internet is a network of networks. If we zoom into them, networks work on BGP. That’s how important BGP is!

4. Why is BGP used?

Border Gateway Protocol (BGP) works as a GPS for the packets of information. The BGP comes up with the best possible route for the packets to travel. It takes into consideration various factors, one of them being the situation of the network nodes.

BGP is designed for the following functions:

Exchange routing information
Exchange reachability information between autonomous systems on the Internet.

Each BGP speaker is called a peer, and exchanges routing information with its neighboring peers as network prefix announcements.

An Autonomous System (AS) doesn’t need to be connected to the other AS to know its network prefix.

BGP chooses the most suitable route on the basis of collected information such as an organization’s routing policy, based on cost, speed and reliability, etc.

5. Why is BGP used over OSPF?

Both BGP and OSPF are dynamic routing protocols. However, there are a few reasons why BGP is used over OSPF. These reasons are mentioned below:

OSPF is an intra-domain routing protocol and it uses link routing protocol. BGP, on the other hand, is an inter-domain routing protocol and it uses path vector routing.

OSPF is used to determine the fastest route whereas BGP tells the best path.

Now, why to use BGP over OSPF:

BGP is often used in Wide Area Network (WAN) and IaaS environments.
It is also used for Internet redundancy.
OSPF is used for Local Area Network (LAN) and data center.
BGP is primarily used in large networks.

Through the above-mentioned pointers, it can be concluded that BGP is better than OSPF.

6. Is BGP faster than OSPF?

OSPF has faster convergence time than OSPF. Network convergence is the is the speed at which a router adjusts path used to a destination network in the times of network outrage.

OSPF works better in Local Area Network (LAN) and private data centers.

7. What is the AD value of BGP?

Administrative Distance (AD) is a value that a router uses in order to choose the best path.

It helps the router to select the best path when there are two or more different routes to the same destination from two different routing protocols.
The AD value is used to rank routes from most preferred route to the least preferred route.
The most-preferred route has the lowest AD value while the least-preferred route has the highest AD value.

8. What is OSPF used for?

Open Shortest Path first (OSPF) is also a routing protocol such as BGP. It is an Interior Gateway protocol. OSPF is used for the following:

OSPF is used in large and very complex networks.
OSPF is a link state routing protocol. Thus, you can use it to converge fast.
OSPF converges faster than distance vector protocols such as BGP.
It is a routing protocol that is used to share routes between routers.
It is relatively easy to configure and is easily understood.
OSPF is used in multi-site networks.
With OSPF, you do not need to add a new route to every other site’s router. OSPF can automatically update the routing tables of various routers.

9. Do home routers use BGP?

Yes, BGP is used by routers present at our homes. BGP helps to route your e-mails and web requests across the Internet. In short, Internet routing cannot happen without BGP.

10. Why is BGP not a routing protocol?

BGP is an inter-domain routing protocol. It uses path vector routing, with the routing operations performed between two or more autonomous systems. BGP works on finding the best path possible.

11. What are LSA types?

OSPF communicates by using Link State Advertisement (LSA) to communicate for the Internet Protocol (IP). OSPF uses a Link State Database (LSDB) and it uses LSA to fill it up.

OSPF consists of many types of LSAs. There are given below:

LSA Type 1: Router LSA

In this LSA, you can find the list of all the directly connected links of this router. These types of routers always stay within the area.

LSA Type 2: Network LSA

This type of LSA is constructed for multi-access networks. Network LSAs are made by DR.

LSA Type 3: Summary LSA

The summary LSA is developed by the ABR. This is why ABR will generate a summary ASBR LSA. It will consist of the router ID of the ASBR.

LSA Type 4: Summary ASBR LSA

The summary ASBR LSA consists of the router ID of the ASBR in the link-state routing field. It makes it easy for other routers to find ASBR.

LSA Type 5: Autonomous System External LSA

These are generated by the external ASBR.

LSA Type 6: Multicast OSPF LSA

It is not used and is not supported.

LSA Type 7: Not-so-stubby area LSA

It is also referred to as not-so-stubby (NSSA) LSA. NSSAs do not allow external LSAs which are Type 5 LSA. With LSA Type 7, you can allow them.

LSA Type 8: External Attribute LSA for BGP

12. What is RIP OSPF EIGRP BGP?

RIP:

Routing Information Protocol (RIP) is a distance vector routing protocol.
It can be used to configure the hosts as a part of a RIP network.

OSPF:

OSPF is a link-state routing protocol.
It is developed for IP networks.
It is based on the Shortest Path First (SPF) algorithm.
It comes under the group of interior gateway protocols.

EIGRP:

Enhanced Interior Gateway Routing Protocol (EIGRP) is a network protocol.
It allows routers to exchange information in a better way than the network protocols that were present earlier.
It is a dynamic routing protocol used for routing and configuration decisions.

BGP:

BGP is the biggest routing protocol in the world.
It manages the trusted and untrusted routes.
It enables routing through autonomous systems instead of routers.
It is the slowest routing protocol in the world.
It is primarily used for service providers.
It can also be used for enterprise customers.

13. When should BGP not be used?

If you only want to connect to an external domain and if there is only one connection then you should not use BGP.

It’s a Wrap!

We have summed up the Cisco BGP interview questions and answers altogether. Also, the questions and answers consist of scenario-based BGP questions, BGP troubleshooting questions and BGP attribute questions and answers.

Go over all these questions and you are all set to ace your exam!

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Most Asked CCIE Interview Questions – Answered with Examples

April 20, 2023March 12, 2023 by Aakriti

Hereby, we present you with the simplest CCIE Interview Questions and answers. We hope you find this helpful. We have covered the following topics in our blog. These include

CCIE Routing and Switching
IP Routing
OSPF
BGP
Quality of Service (QoS)

We have often heard and are aware that getting Cisco Certified Internetwork Expert (CCIE) certification is an uphill task. Although the list of things one needs to know is long, do not worry. We have tried to simplify the same for you.

Firstly, contrary to popular belief you don’t need a hefty number of questionnaires to ace the CCIE exam. Yet, you do need to prepare well for the exam. This blog is all about the basic concepts involved in the CCIE examination. We have included mostly the CCIE enterprise questions. You can get the help of this guide to get going.

At times, it becomes really difficult to keep up with all the concepts. Hence we have made it easy for you here.

Most of the time people run after complex concepts and forget about the basic ones.

We are mostly focusing on the basic concepts in the early part of this blog. Followed by it will be some higher-level questions. If your basics are not clear, you cannot do anything about the difficult concepts. Even the interviewers ask basic questions in a CCIE interview.

1. What is a Firewall?

A firewall is a protection wall (a device) present between a trusted and a non-trusted network.

It is a network security device that filters incoming and outgoing traffic.
It does so by checking out the previous activity on a particular website based on the security policies of that website.
Firewall protects an inside network from unauthorized access by users present outside a network.
It also protects inside networks from each other.
For example, it keeps a management network away from a user network.

2. What are the security levels in Cisco ASA?

The Cisco ASA uses ‘security levels’ to estimate how much can it trust a particular network that is attached to a respective interface.
It looks at the security levels that can be configured anywhere between 0-100.
The higher the number, the higher the trust in that network.
The lower the number, the lesser the trust in that network is.
ASA allows the flow of traffic from higher security level to a lower security level only, ny default.

3. What is DMZ (Demilitarized Zone) Server?

Demilitarized zone (DMZ) is a separate network behind the firewall.
It allows you to access some network resources such as Web server or FTP server that are available to outside users.
These are placed in the DMZ server.
DMZ only includes public servers. An attack there can only affect the servers but not the inside network.
The firewall allows limited access to DMZ.

4. What is a Transparent Firewall and what is the need for it?

ASA acts as a Layer 2 device in Transparent Mode like a bridge or switch. It forwards Ethernet frames based on destination MAC-address.

The need of Transparent firewall:

It is difficult to deploy a new firewall in an already existing network.
The process needs address reconfiguration, network topology changes, current firewall, etc.
But transparent firewall can be easily inserted in an existing network.
Transparent firewall insertion does not need any changes.
It does not need to readdress or reconfigure the devices.

5. What features are not supported in Transport mode?

The following features are not supported in Transport mode:

Dynamic routing
Multicasting
QOS
VPNs like IPsec and WebVPN cannot be exited.
ASA cannot act as a DHCP relay agent.

6. What is Unit Health Monitoring in Failover? How does failover happen?

The health of a unit is measured by the ASA unit. It does so by monitoring the failover link. When a unit does not receive three continuous ‘hello’ messages on the failover link, it sends hello messages on each interface.

These interfaces include failover interface. It checks if the other unit responses or not.

On the basis of the responses from other units, it takes the following actions:

If ASA receives a response on the failover interface, then it does not failover.
If the ASA does not receive a response on the failover link, but if it does receive a response on another interface, then the unit does not failover. The failover linked is marked ‘failed’.
If the ASA does not receive a response on any interface, then the standby unit changes to active mode and separates the other unit as failed.

7. Tell us some of the commands that are not replicated to standby unit.

All types of copy commands except for # copy running-config startup-config.

All types of the write command except for # write memory.

8. What is the difference between Stateful failover and Stateless failover?

Stateful failover	Stateless failover
After a failover happens, the same connection information is available at the new active unit.	When a failover happens, all active connections are exited.
Clients do not need to reconnect to keep the same connection session.	Clients need to re-establish connections when the new active unit takes over.

9. What are the various types of ACL in Firewall?

The different types of ACL in Firewall include:

Standard ACL
Extended ACL
Ethertype ACL (Transparent Firewall)
Webtype (SSL VPN)

10. Name some of the concepts that are not possible to configure on ASA.

Line VTY can’t be configured on ASA.
Wildcard mask concept is not present in ASA.
Loopback can’t be configured on ASA.

11. Which routing protocols are application layer protocols?

The application layer is the topmost layer of the OSI model. The users interact through this layer of the OSI model. It is layer 7 and sits at the top of the Open Systems Interconnection (OSI) communication model.

The application layer is NOT an application. It is a component within an application that takes care of the communications to other devices. It is an abstract layer of services that allows the application from the transmission process.

Application Layer protocol:

1. TELNET:

Telnet means TELetype NETwork.
It helps in terminal emulation, that is, it makes one PC look like another.
It is used for managing files on the Internet.
The TELNET command uses the TELNET protocol to talk with a remote device/system.
The port number of telnet is 23.

Steps to enable Telnet server:

switch# configure terminal
switch(config)# feature telnet
switch(config)# show telnet server
(Optional) switch(config)# show telnet server
(Optional) switch(config)# copy running-config startup-config

2. FTP:

FTP stands for File Transfer Protocol.
It is a standard Internet protocol provided by TCP/IP.
It is used for transmitting files from one host to another.
It is used to transfer web page files from their creator to the computer.
Port number is 20 for data and 21 for control.

Steps to turn on FTP server on Cisco router:

Connect the Cisco router using a telnet client.
Type IP address for the router.
Press the client’s connect button.
Type in the password for the router to complete the connection.
Type “ftp-server enable” on the command line of the terminal.
Tap “Enter” key to enable server capability.
Type “ftp-server topdir <directory>” on the next terminal.
Add directory name for ftp files in place of <directory> to limit ftp access to directory only.
Press “Enter”.

3. TFTP:

TFTP stands for Trivial File Transfer Protocol.
It is the stock version of FTP.
It is a technology for transferring files between network devices.
It is a simplified version of FTP.
The port number is 69.

Steps to start TFTP using commands:

To start TFTP server from the command line, type the tftpd command

tftpd [-l] [-p port] [-t timeout] [-r maxretries] [-c concurrency_limit] [-s maxsegsize] [-f file] [-a archive directory [-a …]] [-b IP address] [directory …]

4. NFS:

It stands for Network File System.
It allows remote hosts to mount file systems over network.
It allows to collect resources onto centralized servers on the network.
The port number for NFS is 2049.

Command to start NFS:

Service nfs start

5. SMTP:

It stands for Simple Mail Transfer Protocol.
It is a part of the TCP/IP protocol.
The port number for SMTP is 25.

Command to start SMTP:

MAIL FROM: <mail@abc.com>

6. LPD:

It stands for Line Printer Daemon.
It is made for printer sharing.
It is the part that receives the request and then processes it.
Daemon means a server/agent.
The port number is 515.

Starting the LPD remote subsystem:

You can start the lpd remote subsystem with startsrc or mkitab command, or SMIT.
Your system must be configured to communicate with a remote print server.
You need to have root authority.
At the system prompt, you need to type smit mkitab_lpd
You can use the following command to start lpd remote subsystem now;

startsrc –s lpd

7. X window:

It is the base protocol of X Window system.
It is used on Unix, Linux and BSD systems.
It can also be used on Microsoft Windows, Mac OS X and many other systems.
It can be used on any modern operating system.
It can cause versions and distributions of Linux to separate.
The port number starts from 6000 and increases by 1 for every server.

The command used to run it:

Run sdm in runlevel 5

8. DNS:

It stands for Domain Name System.
It translates a domain name into the corresponding IP address.
The port number for DNS is 53.

The command used for DNS:

ipconfig/ flushdns

9. DHCP:

It stands for Dynamic Host Configuration Protocol (DHCP).
It provides IP addresses to hosts.
Port numbers for DHCP are 67, 68.

The command used for DHCP:

Clear ip dhcp binding {address | *}

10. SNMP:

It stands for Simple Network Management Protocol.
It collects data by polling the devices on the network from a management station.
The port number of SNMP is 161 (TCP) and 162 (UDP).

The command used for SNMP:

Snmpget –mALL -vl -cpublic snmp_agent_Ip_address sysName.0

10. SNMP:

It stands for Simple Network Management Protocol.
It collects data by polling the devices on the network from a management station.
The port number of SNMP is 161 (TCP) and 162 (UDP).

The command used for SNMP:

Snmpget –mALL -vl -cpublic snmp_agent_Ip_address sysName.0

12. What is Unicast Reverse Path Forwarding (uRPF)?

A unicast reverse-path-forwarding (RPF) is a tool that lowers down the forwarding of IP packets.
It takes care of the IP packets that might be copying an address.
It checks the performance of a forwarding table lookup on an IP packet’s source address.
It also checks its incoming interface.
It follows RFC 2827 for ingress filtering.

13. Name the modes of unicast Reverse Path Forwarding.

There are two modes of unicast RPF:

Strict mode
Loose mode

Strict mode is the default mode. This means that the switch forwards a packet only if the receiving interface is the best return path.

14. What is Virtual Routing and Forwarding (VRF)?

Virtual routing and forwarding (RF) is an IP technology.
It allows users to configure multiple routing tables to co-exist within the same router.
These multiple routing instances are independent and can choose different outgoing interfaces.

15. How does OSPF calculate its metric or cost?

The Open Shortest Path First (OSPF) uses “cost” as a value of metric. It uses a Reference Bandwidth of 100 Mbps for cost calculation.

The formula to calculate the cost is:

Cost = Reference Bandwidth / Interface Bandwidth

For example, if the Ethernet is 10 Mbps, OSPF metric cost value is:

100 Mbps/ 10 Mbps = 10.

16. What is the function of the variable IP-OSPF-Transmit-Delay?

The IP-OSPF-Transmit-Delay variable adds a specific time to the age field of an update.
If the delay is not added before reaching over a link, the time in which the link-state advertisement (LSA) reaches over the link is not considered.
The transmit-delay is the estimated time needed for OPSFv2 to send link-state update packets to the connected interface.

17. How often does OSPF send out link-state advertisements (LSAs)?

OSPF sends out LSAs when the LSA that are originated by OSPF itself.
It sends out LSAs when LSA age reaches link-state refresh time, that is 1800 seconds.

18. How does OSPF use two Multilink paths to transfer packets?

OSPF uses the metric costs.
The metric cost is related to the bandwidth.
If there are equal cost paths, OSPF installs both routes in the routing table.
If one of the links fails out of multilink, OSPF does not send all the traffic to the second multilink.
If the first multilink reaches 100% of its bandwidth, OSPF does not send any traffic to the second multilink.
OSPF tries to use both the links equally without any interface use.
The second multilink is only used when the first multilink is down.

19. What are the debugging abilities of EIGRP?

There are two types of debug commands:

Protocol-dependent debug commands
Protocol-independent debug commands

There are also a bunch of show commands that show us the table status, topology table status and EIGRP traffic statistics.

Some of these commands are:

show ip eigrp neighbors
show ip eigrp interfaces
show ip eigrp topology
show ip eigrp traffic

20. What does the EIGRP stuck in active message mean?

EIGRP is a trustworthy protocol.
Any query sent by EIGRP to its neighbors must get a reply within 3 minutes.
If no response is received to all its outstanding queries, it will put the route in Stuck in Active (SIA) state.
This will kill the adjacent neighbors.
The SIA is caused by two events:
The route reported by the SIA has disappeared.
An EIGRP neighbor has not responded to that route’s query.

21. How do you configure BGP?

This is how to configure device as a node in BGP network:

Configure network interfaces.
Configure point-to-point peering sessions.
Configure IBGP sessions between peers.
Configure BGP session attributes such as the autonomous systems for the BGP peers.
Configure routing policy to advertise BGP routes.

There are also some optional steps to follow. Yet these are the necessary steps to configure BGP.

22. What is Quality of Service (QoS)?

Quality of Service (QoS) is the use of technologies that work on a network to regulate traffic. It makes sure that the performance of critical applications does not suffer with the limited network capacity.

It also allows organizations to adjust their network traffic by serving high-performance applications first.

23. What is MQC?

Cisco Modular Quality of Service (MQC) gives a modular and highly extensible framework for deploying QoS. It does so by standardizing the CLI and semantics for QoS features across all platforms. It uses all those platforms that are supported by Cisco IOS software.

Wrapping it Up!

So, we have summed up all the basic concepts that are included in Cisco Certified Internetwork Expert (CCIE) exam. You can easily prepare for your interview exam with these questions. All these topics are very important. As already mentioned, you cannot skip to the difficult concepts without clearing your basic concepts.

You can also check out our other interview questions and answers in our blog section. The questions mentioned are not exhaustive. Please do not rely on these questions to clear your interview. These are the basic answers you need to know.

Also, this blog is all free with answers. You do need to download any pdf and waste your time. We wish you all the best for your interview.

1. What is MPLS?

Multiprotocol Label Switching (MPLS) is a routing technique in telecommunications networks. It is a data forwarding technology that increases the flow and speed of the network traffic. It provides a way to process packets based on their labels.

It uses labels instead of routing table lookups to allow high-end network communications from one network node to the other. MPLS uses the LFIB/forwarding table to transfer labels from one node to the other.

2. What are the benefits of using MPLS?

The benefits of using MPLS are as follows:

Multiple degrees of QoS: Multiple degrees of QoS is supported. They check latency, jitter, and packet loss for various types of traffic such as voice, video, email, and bulk file transfers, etc.
Label-based switching: Convergence is fast due to label-based switching. It cuts the need for routing tables.
IP VPNs: IP VPNs are expandable.
MPLS TE: Network congestion is minimum by using MPLS TE.
Reliable: MPLS is reliable, safe, and trustworthy.

3. What are the MPLS router types?

The following are the MPLS router types:

C – Customer Router
CE – Customer Edge Router
PR – Provider Router
PE – Provider Edge Router

4. What is the difference between a P and a PE router?

P router does not contain customer network routes. These routes are, however, available on the PE router. Also, P routers do not need MP-iBGP. For PE routers, MP-iBGP is a must.

5. Name the types of labels.

The types of labels are:

Explicit Null
Implicit Null
Aggregate Label

6. What are the types of MPLS available?

There are three types of MPLS available:

Layer 2 point to point
Layer 3 IP VPN
Layer 2 VPLS

a. MPLS Layer 2 Point to Point:

The layer 2 point to point MPLS is the best suited for companies that need high bandwidth between a small number of sites.
It is economical.
It is an excellent alternative to high bandwidth leased lines.
Many network operators depend on Layer 2 and Ethernet for their core network infrastructure.
This protocol allows anything running over the LAN to be sent to the WAN without the need for routers to convert packets to Layer 3 (Network Layer).

b. MPLS Layer 3 IP/VPN:

The Layer 3 IP/VPN is best suited for large multi-site enterprises such as retail chains.
They deploy a large number of low bandwidth sites or large corporates

It is the best fit for companies that are:

- In the process of merging: IP/VPNs are scalable for fast deployment.
- Need ‘any to any’ connectivity: a shorter hop count between two local sites is more efficient than -’tromboning’ back into a central point. It is best suited for global networks where latency is increased.
- Preparing for voice and data convergence: to implement a blanket ‘class of service’. It is made simple across multi-site networks.
- Migrating from traditional ATM to IP: ATM has very high maintenance charges.
- Low bandwidth needs at small branch offices.
- Need of only a secure dial-up capability in smaller locations

c. Layer 2 Virtual Private LAN Services (VPLS):

- The VPLS services are popular for delivering Ethernet services.
- They combine both MPLS and Ethernet for customer and carrier benefits.
- IP backbones have been used to provide Internet access as well as IP VPN access.
- VPLS is also known as transparent Ethernet services.
- It works over MPLS and gives benefits of two network types:
  - Ability to operate a multipoint network
  - Pass all traffic at Layer 2 over the WAN
- VPLS is popular among TV broadcasters, the financial sector and media houses.

7. What is the difference between VPN and MPLS?

VPN:

VPN is referred to as Virtual Private Network.
It could be configured using GRE tunnels.
If you want a full mesh then the administrator needs to set u n*n-1 tunnels.

MPLS:

In the case of MPLS VPN, CPE works in the full mesh by default.
It works in full mesh form because of the route-target.

8. Can you make your PE router a P?

You need to remove the Border Gateway Protocol (BGP) configurations to make your PE a P. After you do that, it will not participate with the customer network.

9. If your LDP router ID, OSPF router ID and BGO router ID are different, will it work to forward the traffic of customers or not?

The BGP router ID and the LDP router ID should be the same if SP is using labels only for loopbacks. If labels are generated for each and every route then there is no problem at all.

10. What protocol is used by MPLS?

MPLS uses the Tag Distribution Protocol (TDP) or Label Distribution Protocol (LDP) protocols.

Tag Distribution Protocol (TDP):

Tag Distribution Protocol (TDP) is a two-party protocol. It runs over a connection-oriented transport layer with guaranteed sequential delivery.

Label Distribution Protocol (LDP):

Label Distribution Protocol (LDP) is a protocol used to establish MPLS transport LSPs when there is no need for traffic engineering. It establishes LSPs that follow the existing IP routing table. It is best suited for establishing a full mesh of LSPs between all of the routers on the network.

11. What is penultimate hop popping?

Penultimate hop popping is a method of reducing label lookups on the egress router. It is done by the one-hop before the egress router.

12. What are the functions done by MPLS?

The following are the functions done by MPLS:

PUSH (Adding the Label)
POP (Removing the Label)
SWAP (Changing the Label)

13. What is downstream on demand?

The downstream router is responsible to advertise the label first to the upstream router when the downstream on-demand method is selected.

The upstream router is the router that advertises the labels to its downstream router after receiving label bindings from it.

14. What is the difference between VPNv4 and IPv4 address families?

We use the IPv4 address family to always accept and forward IP packets to customers.

When the customers’ packets are being received by PE, they become labeled and forward packets to different PE/RR. For this, an address family VPNv4 is needed.

In other words, we can say that IPv4 address-family is being used for customers. VPNv4 address-family is used by SP core.

15. What is SYSVOL?

The SysVOL folder has the server’s copy of the domain’s public files. The contents such as users, group policy, etc. of the SysVOL folders are replicated to all domain controllers in the domain.

16. MPLS works on which layer?

It works between layer 2 and layer 3.

17. What is the difference between RD and RT?

RT is an extended community. RD is not an extended community.

18. How to filter MPLS labels?

MPLS filters can be labeled by using ACLs.

19. Two routers are having 4 equal-cost links, how many LDP sessions will be established?

Only one session will be established between the two routers having 4 equal-cost links.

FAQs

What is MPLS in Networking?

Multiprotocol Label Switching (MPLS) is a routing technique in telecommunications networks. It is a data forwarding technology that increases the flow and speed of the network traffic.

What does MPLS use to transfer from one node to another?

MPLS uses the LFIB/forwarding table to transfer labels from one node to the other. It uses labels instead of routing table lookups to allow high-end network communications from one network node to the other.

What are the benefits of using MPLS?