The following are some basic Cisco commands used for troubleshooting BGP in non-VRF and VRF environments.


Show a list of configured VRF's

        Show ip vrf

To see a quick status of all BGP connections, on a non-vrf router and a vrf router,

        show ip bgp summary
        show ip bgp vpnv4 vrf <name> summary

To see BGP routes, in the default table or an explicit VRF,

        show ip bgp
        show ip bgp vpnv4 vrf <name>

To see what routes you're getting from a neighbor, use one of these

        show ip bgp neighbor <IP-address-of-neighbor> routes
        show ip bgp vpnv4 vrf office neighbors x.x.x.x received-routes

  To see what routes you're sending to a neighbor, use the command

        show ip bgp neighbor <IP-address-of-neighbor> advertised-routes
        show ip bgp vpnv4 vrf office neighbors x.x.x.x advertised-routes

 To see what routes you're getting from an AS, use the command

        show ip bgp regexp <regluar-expression-for-an-AS>

 To clear a BGP session:

        clear ip bgp <ip-address of neighbor>

Notes: 

• The same VPNv4 session is used to carry all VRF information, so it will clear all VRF's, not just 1

• From my understanding, the use of "soft in" triggers an automatic ROUTE-REFRESH message to neighbors to resend their routing advertisements without dropping the neighbor.

Commands to configure VRF BGP routing - In Config Mode

ip routing
Enables IP routing on the device

ip vrf <name>
Names the VRF, and enters VRF configuration mode.

rd 2:2
An RD is a route-distinguisher, and it does just that, distinguishes this VPN, or routing table from others.

route-target export 2:2
route-target import 2:2
An RT is a route-target and allows the routes to be imported and exported into and out of the VRF.



When BGP is not behaving correctly, a way to temporarily stop peering with a neighbor is to use the following command:

        router bgp 194
        neighbor <ipaddress>
        password xxx

or on VRF enabled devices
   
      router bgp 1
      address-family ipv4 vrf <name>
      neighbor <ipaddress>
      password xxx

Since the other router doesn't have the same password, the two routers will stop talking to one another, without you having to do anything else. Later, when the problem is resolved, simply remove the line to reestablish peerage.

To see what's happening with BGP, use the commands

        terminal monitor
        debug ip bgp events

To find out who owns and Autonomous System, go to http://www.arin.net/ and type AS<number> in search. 

Note - AS64512 to AS65535 are Private use Autonomous System Numbers for Internal use only, think Private IP ranges:
 
192.168.0.0 - 192.168.255.255 (65,536 IP addresses)172.16.0.0 - 172.31.255.255 (1,048,576 IP addresses)
10.0.0.0 - 10.255.255.255 (16,777,216 IP addresses)

I hope this may be of use and I welcome any feedback, 

please feel free to comment below.

February networking question

The February edition of random networking questions.

Another 10 questions to get the grey matter ticking :-)

1. A flat network can be best described as...

A) Physically flat
B) One collision domain
C) One broadcast domain
D) One VLAN

2. Where does routing occur within the DoD TCP/IP reference model?

A. application
B. internet
C. network
D. transport

3. What layer of the OSI model provides the physical transmission of data, handles error notifications, network topology and flow control?

A) Physical
B) Data Link
C) Presentation
D) Session
E) Transport

4. Bridges can only have one spanning tree instance, while switches can have many.

A) True
B) False

5. A Cisco router is booting and has just completed the POST process. It is now ready to find and load an IOS image. What function does the router perform next?

A. It checks the configuration register.
B. It attempts to boot from a TFTP server.
C. It loads the first image file in flash memory.
D. It inspects the configuration file in NVRAM for boot instructions.

6. A CIDR value of /30 equates to what subnet mask?

A) 255.255.255.253
B) 255.255.255.128
C) 255.255.255.248
D) 255.255.255.252

7. What is the maximum size of an Ethernet packet when the frames have ISL tagging?(Include the size of headers and CRC)

A) 64 bytes
B) 1500 bytes
C) 1518 bytes
D) 1522 bytes
E) 1548 bytes

8. Which item represents the standard IP ACL?

A. access-list 110 permit ip any any
B. access-list 50 deny 192.168.1.1 0.0.0.255
C. access list 101 deny tcp any host 192.168.1.1
D. access-list 2500 deny tcp any host 192.168.1.1 eq 22

9. Which two commands correctly verify whether port security has been configured on port FastEthernet 0/12 on a switch? (Choose two.)

A. SW1#show port-secure interface FastEthernet 0/12
B. SW1#show switchport port-secure interface FastEthernet 0/12
C. SW1#show running-config
D. SW1#show port-security interface FastEthernet 0/12
E. SW1#show switchport port-security interface FastEthernet 0/12

10. Which protocol can cause overload on a CPU of a managed device?

A. Netflow
B. WCCP
C. IP SLA
D. SNMP













1. Correct Answer C

A switched network can be described as a flat network because broadcasts are transmitted to every device.

2. Correct Answer B

The picture below shows the comparison between TCP/IP model & OSI model. Notice that
the Internet Layer of TCP/IP is equivalent to the Network Layer which is responsible for
routing decision.

3. Correct Answer B

http://en.wikipedia.org/wiki/Data_Link_Layer

4. Correct Answer A

Bridges are software based and can only have one spanning-tree instance per bridge, while switches are hardware based and can have many.

5. Correct Answer A

Default (normal) Boot Sequence
Power on Router - Router does POST - Bootstrap starts IOS load - Check configuration
register to see what mode the router should boot up in (usually 0x2102 to read startupconfig
in NVRAM / or 0x2142 to start in "setup-mode") - check the startup-config file in
NVRAM for boot-system commands - load IOS from Flash.

6. Correct Answer D

http://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing#Assignment_of_CIDR_blocks

7. Correct Answer E

Cisco's proprietary VLAN tagging (ISL) has a maximum frame size of 1548 bytes.
IEEE 802.1q VLAN tagging has a maximum frame size of 1522 bytes.

8. Correct Answer B

The standard access lists are ranged from 1 to 99 and from 1300 to 1999 so only access
list 50 is a standard access list.

9. Correct Answers C and D

We can verify whether port security has been configured by using the “show runningconfig”
or “show port-security interface” for more detail. An example of the output of “show
port-security interface” command is shown below:

10. Correct Answer D

Sometimes, messages like this might appear in the router console:
%SNMP-3-CPUHOG: Processing [chars] of [chars]
They mean that the SNMP agent on the device has taken too much time to process a
request.

How did you go? very random selection huh :-)

let me know if you found any errors in the comments, more coming .

“Don't cry because it's over, smile because it happened.”

Dr. Seuss

 

Networking questions part 1

I'm going to try to submit questions at least once a month this year (hopefully more often)

Here's the first batch, enjoy....

1. What layer of the OSI Reference Model sends and receives bits and specifies the electrical, mechanical, procedural and functional requirements for maintaining a physical link between end systems?

A) Session
B) Transport
C) Network
D) Data Link
E) Physical

2. What Cisco IOS keyboard shortcut recalls the oldest command in the command history, beginning with the most recent command?

A) Ctrl+B
B) Ctrl+E
C) Ctrl+U
D) Ctrl+N
E) Ctrl+P

3. What does Router(config)# no access-list 1 command achieve?

A) Removes Access List 1
B) Disables ACL on interface 1
C) Nothing, this is not a Cisco command

4. When would an interface need a clock rate?

A) When the interface is DTE
B) When the interface is DCE

5, What is Cisco's default NAT table entry timeout (translation timeout)?

A) 1 hour
B) 12 hours
C) 24 hours
D) 36 hours
E) 48 hours

6. What is the maximum number of subnets given the following?

192.168.10.0 255.255.255.192
(Assume ip subnet-zero is enabled)

A) 4
B) 8
C) 16
D) 32
E) 64

7. What is port 21 used for?

A) FTP data
B) FTP program
C) Telnet
D) SMTP
E) TFTP

8. What does the term "Logical address" refer to?
A) MAC address
B) Physical address
C) IP address
D) Link-layer address

9. What is the maximum number of hosts you can assign to a class C network if it is not subnetted?

A) 1024
B) 254
C) 32
D) 512
E) 65025

10. A router has two Fast Ethernet interfaces and needs to connect to four VLANs in the local network. How can you accomplish this task, using the fewest physical interfaces and without decreasing network performance?

A. Use a hub to connect the four VLANS with a Fast Ethernet interface on the router.
B. Add a second router to handle the VLAN traffic.
C. Add two more Fast Ethernet interfaces.
D. Implement a router-on-a-stick configuration.

1. Correct Answer E

http://en.wikipedia.org/wiki/Physical_Layer

2. Correct Answer E

Keyboard Shortcut Action

Up Arrow Displays your previous commands.  (command history)
TAB Key Completes a partially typed CLI commands.
CTRL+Z Takes you back to Privileged EXEC Mode.

CTRL+A Places the cursor at the beginning of a line.
CTRL+E Places the cursor at the end of a line.
CTRL+R Redisplays the current command line.
CTRL+W Erases a word (behind the cursor).
CTRL+U Erases an entire line.

3. Correct Answer A

If you wish to remove an access-list, you use the no access-list (list #) command.

4. Correct Answer B

Cisco routers are DTEs by default (Data Terminal Equipment). The DCE (Data Circuit-Terminating Equipment) at the other end of the connection must supply a clock rate to the DTE.

5. Correct Answer C

When an entry is placed into the NAT table a timer begins, the duration of this timer is called the translation timeout, defaulted to 24 hours on Cisco routers.

6. Correct Answer A

192.168.10.0 is a class C address.  The subnet mask 255.255.255.192 implies 2 bits are borrowed.
22 = 4 subnets

7. Correct Answer B

File Transfer Protocol (FTP) is a network protocol used to copy files from one host to another over a TCP/IP-based network.
A client makes a TCP connection to the server's port 21. This connection remains open for the duration of the session called the control connection, with a second connection, called the data connection, opened by the server from its port 20 to a client port required to transfer file data.

8. Correct Answer C

A Logical address is normally a 32-bit IP address assigned to each host in an IPv4 network.

A Physical address is a unique 48-bit flat address normally burned into the ROM of the NIC card, and therefore cannot be changed. It is divided into 24-bit vendor code and 24-bit serial address.

9. Correct Answer B

For class C the number of bits for host address portion is 8. So 2^8 -2 = 256-2 = 254 hosts.

10. Correct Answer D

A router on a stick allows you to use sub-interfaces to create multiple logical networks on a
single physical interface.

How did you go? If you disagree with any of my answers or find errors, please leave a comment. More coming soon..stay tuned :-)

I remind myself every morning: Nothing I say this day will teach me anything. So if I'm going to learn, I must do it by listening.
Larry King

Networking Questions 2016 Part 5

Here are some more very random networking questions based around the CCNA type of exam head scratchers... :-)

1. What type of NAT allows you to map multiple unregistered IP addresses to a single registered IP address?

A) Static NAT
B) Dynamic NAT
C) Overloading (Port Address Translation)

2. Each port on a switch is a separate broadcast domain?

A) True
B) False

3. Inter-Switch Link and IEEE 802.1Q are types of...

A) Spanning Tree Protocol
B) Trunking method
C) Ethernet
D) Routing protocol

4. What statement is not correct when talking about a shared-medium Ethernet LAN?

A) The data frame broadcast delivery nature of Ethernet can have a negative affect on performance
B) Adding repeaters and hubs to an Ethernet network can increase latency
C) Ethernet is a best-effort delivery service
D) Collisions are caused by CSMA/CD on an Ethernet network

5. What TCP/IP layer are TCP and UDP protocols associated with?

A) Application
B) Host-to-Host
C) Internet
D) Network Access

6. What IOS command would you issue in privileged-mode to change the Cisco router configuration stored on TFTP?

A) config t
B) config mem
C) config net
D) config tftp









1. Answer: C

PAT (Port Address Translation) allows you to map multiple unregistered IP addresses to a single registered IP address.

2. Answer: B

Switches create separate collision domains but a single broadcast domain.

http://en.wikipedia.org/wiki/Broadcast_domain

3. Answer: B

Both Inter-Switch Link and IEEE 802.1Q are types of VLAN identification.  Inter-Switch Link (ISL) is a Cisco proprietary protocol whereas IEEE 802.1Q is a standard method of frame tagging.
4. Answer: D (did you get the "not"?)

Carrier Sense Multiple Access / Collision Detection (CSMA/CD) is a set of rules determining how network devices should respond when two devices try to use the shared medium simultaneously.

http://en.wikipedia.org/wiki/Carrier_sense_multiple_access_with_collision_detection
5. Answer: B

TCP and UDP protocols are associated with the Transport layer of the TCP/IP model, which is sometimes referred to as the "host-to-host transport layer".

http://en.wikipedia.org/wiki/Internet_Protocol_Suite

Internet protocol suite examples:
Application layer
BGP · DHCP · DNS · FTP · HTTP · IMAP · LDAP · MGCP · NNTP · NTP · POP · ONC/RPC · RTP · RTSP · RIP · SIP · SMTP · SNMP · SSH · Telnet · TLS/SSL · XMPP ·
Transport layer
TCP · UDP · DCCP · SCTP · RSVP 
Internet layer
IP  (IPv4 · IPv6) · ICMP · ICMPv6 · ECN · IGMP · IPsec  
Link layer
ARP · NDP · Tunnels  (L2TP · PPP · MAC  (Ethernet · DSL · ISDN · FDDI ·

6. Answer: C

To change the router configuration stored on TFTP you use configure network (config net)


More random question coming soon :-)

   “Employ your time in improving yourself by other men's writings, so that you shall gain easily what others have labored hard for.”

? Socrates

Networking Questions 2016 Part 4

Been a while since we've stretched the grey matter, time to get to some more thinking with these random networking questions :-) Have fun.


1. In which layer of the OSI model does framing occur?

A) Layer 3
B) Physical layer
C) Application layer
D) Layer 2
E) Network layer

2. How would you view the current Cisco Configuration Register value?

A) show config-register
B) show reg
C) show config
D) show version

3. What does 'r' stand for in the capabilities of a Cisco device in the output of a show cdp neighbor command?

A) Repeater
B) Router
C) IGMP
D) Host
E) Switch

4. Ethernet technology relates to which type of network?

A) WAN
B) LAN
C) MAN
D) SAN
E) All of the above

5. What is the numerical value of the Bridge Priority held by Catalyst switches?

A) 32500
B) 32768
C) 100
D) 1024
E) 32700

6. What OSI layer does the following refer to?

"Establishes availability of intended communication partners, establishes agreement on procedures regarding error recovery and data integrity and synchronizes networked applications"

A) Transport layer
B) Session layer
C) Datalink layer
D) Application layer
E) Presentation layer

7. PPP can be used over what types of serial connections?

A) Synchronous
B) Asynchronous
C) Both
D) Neither

8. Which of the following could be a valid MAC address?

A) 00-08-74-CE-B7-90
B) 192.168.0.1
C) FFFF.FFFF.FFFF.FFFF
D) 255.255.255.240




-->
Clickbank.com Ads





1. Answer: D

The protocol data unit (PDU) of the Data Link layer (Layer 2) is the frame.  Data passed down from the Network layer is framed at layer 2 before being sent on to the Physical layer.

http://en.wikipedia.org/wiki/Data_Link_Layer

2. Answer: D

You can see the current value of the configuration register by using the show version command.
eg:
Configuration register is 0x2102


3. Answer: A

 Router#show cdp neighborsCapability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge                  S - Switch, H - Host, I - IGMP, r - Repeater

 4. Answer: B

The IEEE standards relating to Ethernet technology were originally developed for local area networks.
This is the Cisco definition, although in practice this definition is very blurred :-).

 5. Answer: B

The Bridge Priority is the numerical value held by switches. All Catalyst switches have a default priority of 32768. To determine the root bridge you combine the priority of each bridge with its MAC. If two switches have the same priority value the lowest MAC address becomes the root bridge.

6. Answer: D


The Application layer of the OSI model (layer 7) establishes availability of intended communication partners, establishes agreement on procedures regarding error recovery and data integrity and synchronizes networked applications.

http://en.wikipedia.org/wiki/Application_Layer


7. Answer: C 

Point-to-Point Protocol (PPP) can be used over ISDN (synchronous) and dial-up (asynchronous) connections.

8. Answer: A

The standard format for printing MAC addresses is six groups of two hexadecimal digits, separated by hyphens (-) or colons (:) e.g. 00-08-74-CE-B7-90, 00:08:74:CE:B7:90.
Another convention commonly used is three groups of four hexadecimal digits separated by dots e.g. 0573.4567.19ab.

How did you go??

I told you they would be random, more coming, stay tuned.

Cisco CLI Analyzer 2.0 Released - IOS and NX-OS support added!

Cisco CLI Analyzer 2.0 Powered by TAC What's New? New name: Now that we support IOS and NX-OS the ASA CLI Analyzer is now the "Cisco CLI Analyzer".   Note: If you currently use Output Interpreter please migrate over to CLI Analyzer as it has more advanced diagnostic capabilities. Enhancements:   Advanced System Diagnostics for IOS, IOS-XE, IOS-XR. XR includes "Virtual TAC" providing deep diagnostics and customized analysis. New Contextual Help & Highlighting and System Diagnostic checks added! Platform Contextual Help & Highlighting System Diagnostics ASA 651 131 IOS, IOS-XE 705 221 IOS-XR 6,201 119 NX-OS 250 N/A •Device detection: Information such as serial #, software version, model and device type are automatically added to Cisco supported devices (ASA, IOS*, NX-OS) within the Devices tab. •Contextual Menu: Added the ability to highlight text in the CLI and search cisco.com •Request new CHH content •Keyboard shortcuts: Tab through your sessions (CTRL+Tab), open a new session (ALT+Q) and Search Highlight (CTRL+F) Security: Save CCO credentials using Master Password. Overview: In this release of Cisco CLI Analyzer 2.0 we added advanced TAC tools and knowledge to support IOS, IOS-XE, IOS-XR, NX-OS and new ASA content. UCS tools and advanced Case automation capabilities are in the pipeline! What's next?    Upgrade to 2.0 now!  The Cisco CLI Analyzer is your ticket to the most current and powerful tools from Cisco TAC.   Free Cisco labs for CCNA, CCNP and CCIE students! Presented by René Molenaar - CCIE #41726

 
 

Networking Questions 2016 - Part 3

The next installment of Six more random networking questions for your enjoyment :-)


1.  When STP is converging no data can move through the switched network.

A) True
B) False

2. What should be carried out within the Cisco hierarchy at the distribution layer?

A) ACL
B) Security and network policies
C) VLANs
D) WAN access
E) All of the above

3. What protocol range would you use for IP in ACLs?

A) 1-99
B) 800-899
C) 200-299
D) 1000-1099

4. If applied to an interface what would this ACL do?

Router(config)#access-list 25 deny 172.32.10.0 0.0.0.255
Router(config)#access-list 25 permit any

A) Deny traffic from the 172.32.10.0 network
B) Deny SMTP traffic from the 172.32.10.0 network
C) Deny traffic from the host 172.32.10.0
D) Deny SMTP traffic from the host 172.32.10.0
E) Allow all traffic

5.  Your network features a combination of Cisco, 3COM and Netgear switches. You have been tasked to set up VLANS on your switched network.

What trunking method should you use?

A) Inter-Switch Link
B) IEEE 802.1Q
C) You can't create VLANs by combining switches from different vend

6. When you connect to a remote router "out-of-band", via what port would you connect with?

A) Console port
B) Auxiliary port
C) Ethernet port
D) Serial port

Free Cisco labs for CCNA, CCNP and CCIE students!
Presented by René Molenaar - CCIE #41726

1. Answer A 

http://en.wikipedia.org/wiki/Spanning_tree_protocol

2. Answer E

Distribution layer (Workgroup layer): Ensures packets are properly routed between subnets and VLANs using LAN-based routers and Layer 3 switches. In the Distribution layer are:

• Firewalls, security, network policies, and network address translation (NAT) are configured.
• Routing between workgroups and VLANs is accomplished.
• Access lists, packet filtering, and queuing are implemented.

3. Answer A

Router#configure terminal
Router(config)#access-list ?
 <1-99>  IP standard access list
 <100-199> IP extended access list
 <1100-1199> Extended 48-bit MAC address access list
 <1300-1999> IP standard access list (expanded range)
 <200-299> Protocol type-code access list
 <2000-2699> IP extended access list (expanded range)
 <700-799> 48-bit MAC address access list
 rate-limit Simple rate-limit specific access list
4. Answer A

This standard ACL denys traffic from the 172.32.10.0 network and allows everything else.

5. Answer B 

ISL is a Cisco proprietary frame tagging method and therefore only works with Cisco switches.
IEEE 802.1Q is the networking standard that supports virtual LANs (VLANs) on an Ethernet network.

6. Answer B

When a router is out-of-band (out of the network) you would connect remotely via a modem attached to the auxiliary port.

Check back regularly, more questions every week 

(if time permits).

   “I seldom end up where I wanted to go, but almost always end up where I need to be.”

― Douglas Adams

Networking Questions 2016 - Part2

Another half a dozen random networking posers to get you thinking, have fun :-)


1. Lets start simple, What is port 23 used for?

A) FTP data
B) FTP program
C) Telnet
D) SMTP
E) TFTP

2. What is true about the MAC address?

A) Used to identify networks
B) Defined at the Network layer
C) Unique for every networked device in the world
D) Identical to the IP address

3. In a local broadcast all bits set to 1 are received by all hosts on local and remote broadcast domains?

A) True
B) False

4. IGRP advertises routes to interior, system and exterior routes

A) True
B) False

5. What is the correct sequence of Spanning Tree states?

A) Blocking, Listening, Learning, Forwarding, Disabled
B) Disabled, Blocking, Listening, Learning, Forwarding
C) Learning, Listening, Forwarding, Disabled, Blocking
D) Listening, Learning, Forwarding, Blocking, Disabled

6. What do asymmetric switches require?

A) memory buffers
B) extra ports
C) statically assigned ports only
D) high speed CAM






1.  Answer C

The Telnet is a TCP/IP protocol which defines a text based communications session between a client and a host using TCP port number 23.

2. Answer C

MAC addresses are assigned by the manufacturer of a network interface card (NIC) and are stored in its hardware. A MAC address contains the manufacturer's identification number.
The MAC address may also be referred to as the burned-in address, hardware address, Ethernet address or physical address and is part of the Data Link layer, specifically the Media Access Control sub-layer of the Data Link layer.

http://en.wikipedia.org/wiki/MAC_address

3. Answer B

Routers don't forward broadcasts so local broadcasts will stay on the broadcast domain from which they originated.

 4. Answer A

IGRP advertises three types of routes:

Interior routes are routes between subnets in the network attached to a router interface.
System routes are routes to networks within an autonomous system.
Exterior routes are routes to networks outside the autonomous system.

 5.  Answer A

STP switch port states:

Blocking
Listening
Learning
Forwarding
Disabled

A switch does not enter any of these port states immediately except the blocking state. When the Spanning Tree Protocol (STP) is enabled, every switch in the network starts in the blocking state and later changes to the listening and learning states.

6. Answer A

With ability for support of high bandwidth ports Asymmetric Switches require more Buffer memory for storing and forwarding of packets for fast processing.

Progressively harder ?? stay tuned for more  

- thank you.

“A good teacher can inspire hope, ignite the imagination, and instill a love of learning.”

― Brad Henry

Random Cisco based networking questions - CCNA - Part 9

More network based questions and answers, part nine of the 2015 series, complete with wiki reference links for further reading :-)

1.  What TCP/IP layer are Telnet, FTP, TFTP and SMTP protocols associated with?

A) Application
B) Host-to-Host / Transport
C) Internet
D) Network Access

2. What is not a main switch function?

A) Address learning
B) Frame forwarding
C) Packet forwarding
D) Loop avoidance

3. What layer of the OSI model segments and reassembles data from upper-layer applications and brings them together in the same data stream?

A: Presentation
B: Session
C: Transport
D: Network
E: Data Link

4. VLAN trunk protocol is responsible for?

A) Tracking and monitoring VLANS
B) Consistent VLAN configuration
C) Trunking VLANs across mixed networks
D) Reporting New VLANs
E) All of the above
5. If you are trunking between non-Cisco switches what frame tagging standard should you adopt?

A) 802.1q
B) ISL
C) 802.3q
D) VTP

6. If your switch uses shared memory buffering, what would happen if a packet could not be delivered because of a busy destination port?

A) It would delay transmission of all packets in memory
B) It would be sent to the destination port anyway
C) It would wait in a queue while all other packets in memory are transmitted
D) It would drop the packet after an allocated time

7.What is the equivalent of the TCP/IP Network Access layer in the OSI Reference layer?

A) Network
B) Data Link
C) Data Link and Physical
D) Physical
E) Transport

8. What is the Spanning Tree forward delay?

A) The time that is spent in the Listening and Learning states
B) 50 seconds
C) Time taken for a switch to go from Listening to Forwarding
D) Time taken for a switch to go from Blocking to Forwarding



=======================================
A social trading platform at the top of its class. State-of-the-art software, excellent customer support and a trading platform that is not only reliable, but also enjoyable make eToro a top choice when looking for a Forex broker.   

  ===========================================

1. Answer: A

http://en.wikipedia.org/wiki/Internet_Protocol_Suite

2.  Answer: C 

Switches are layer 2 devices and do not look at layer 3 packets.

3. Answer: C

http://en.wikipedia.org/wiki/Transport_Layer

4. Answer: E

VLAN Trunking Protocol (VTP) is a Cisco proprietary protocol that manages the addition, deletion, and renaming of Virtual Local Area Networks (VLAN) on a network.

http://en.wikipedia.org/wiki/VLAN_Trunking_Protocol

5. Answer: A

ISL is a Cisco proprietary VLAN tagging protocol and therefore if you have a multi-vendor switch network you will need to choose the IEEE 802.1q standard instead of ISL.


6. Answer: C

The area of memory where the switch stores the data is called the memory buffer.
The memory buffer can use two methods for forwarding frames:
 
port-based memory buffering
shared memory buffering

In port-based memory buffering frames are stored in queues that are linked to specific incoming ports.

Shared memory buffering deposits all frames into a common memory buffer which all the ports on the switch share.

 7. Answer: C 

The link layer has the networking scope of the local network connection to which a host is attached. It is the lowest component layer of the Internet protocols, as TCP/IP is designed to be hardware independent. As a result, TCP/IP may be implemented on top of virtually any hardware networking technology.

http://en.wikipedia.org/wiki/TCP/IP_model#OSI_and_TCP.2FIP_layering_differences

8. Answer: A

Forward delay — The time that is spent in the listening and learning state, 15 sec by default, but you can tune the time to be between 4 and 30 sec.




Stay tuned for more coming soon :-)