Posted on

Our-Network-Blu-used

Network Information

Network Setup:

  • Utilized multimode fiber (MMF) and single-mode fiber (SMF) cables for connectivity optimization.
  • Connected Optical Line Terminal (OLT) to Core using MMF for high-capacity link.
  • OLT and Optical Distribution Frame (ODF) interconnected using single-mode fiber patch cables for reliability.

Optical Distribution Frame (ODF):

  • ODF equipped with pigtails grouped into bundles of 144 and 78 fibers.
  • Some fibers were unused due to material cost and availability considerations.
  • Configuration allowed effective use of available resources and inventory.

Customer Connections Topology:

  • Employed 12/24 core cables for Customer Termination Outlets (CTOs) connections.
  • CTOs served as distribution points for individual apartments or users.
  • Transitioned from core cables to single-core cables using pigtails for direct apartment connections.

Preference for 24-Core Cables:

  • Utilized 24-core cables more frequently due to their availability and convenience.
  • 12-core cables were used in smaller installations as required.

Team Involvement and Versatility:

  • Small team was actively engaged in various network aspects.
  • Team members addressed challenges and opportunities at all levels of the network.
  • Flexibility and hands-on experience were key factors in network management.

Efficiency in Cable Splicing:

  • Estimated around 45 minutes for splicing 12 cables.
  • Acknowledged that continuous splicing could further optimize this time.
  • Highlighted the team’s hands-on experience contributing to efficient splicing.

Practical Network Design:

  • Design balanced practical considerations with material availability.
  • Emphasized commitment to effective connectivity for users.
  • Prioritized resource utilization and material costs in network decisions.
Posted on

Fiber-optic connector Question

Fiber-Optic Connector Properties

Properties of a Fiber-Optic Connector

  • Option A: A Duplex Multimode LC connector is similar to an SC connector but uses a duplex connector.
  • Option B (Highlighted): An LC connector is a smaller version of the straight-tip connector.
  • Option C: A straight-tip connector locks securely with a “twist-on/twist-off” bayonet-style mechanism.
  • Option D: An LC connector is a widely-adopted LAN and WAN connector that uses a push-pull mechanism to ensure positive insertion.
Posted on

Features of an IPv4 routing table on a router

Which two statements describe features of an IPv4 routing table on a router?

A: The netstat -r command can be used to display the routing table of a router.

Key Point: The netstat -r command displays the IPv4 routing table on a router, showing network destinations and corresponding next-hop routers or exit interfaces.

B: Directly connected interfaces will have two route source codes in the routing table: C and S.

Not Correct: Directly connected interfaces will have one route source code in the routing table, which is “C” (for directly connected network). There is no “S” source code associated with directly connected interfaces.

C: The routing table stores information about routes derived from the active router interfaces.

Not Correct: The routing table stores information about routes to different network destinations, including those learned through various methods like static routes, dynamic routing protocols, and connected interfaces. It is not limited to routes derived from the active router interfaces only.

D: If a default static route is configured in the router, an entry will be included in the routing table with source code S.

Key Point: When a default static route is configured on a router, it is represented in the routing table with the source code “S”. A default route is used to direct packets with unknown destination addresses to a specific next-hop router or exit interface.

E: The routing table lists the MAC addresses of each active interface.

Not Correct: The routing table contains information about IP routes and their next-hop IP addresses or exit interfaces, but it does not include MAC addresses. MAC addresses are relevant at the data link layer (Layer 2) for local communication within the same network segment, whereas the routing table deals with IP addresses at the network layer (Layer 3).

Posted on

Default gateway address of a client device

Correct Answer: C – The IPv4 address of the router interface that is connected to the same LAN

Explanation:

The default gateway is the IP address of the router that serves as the exit point for traffic from a local network to reach other networks, such as the internet or remote networks. When a client device wants to communicate with devices on other networks, it sends the traffic to the default gateway, and the router handles the forwarding of the data to the appropriate destination.

In a local area network (LAN) environment, the default gateway should be set to the IP address of the router interface that is connected to the same LAN as the client device. This router interface acts as the gateway for the client device to reach destinations outside of its local network.

Example: Suppose a client device with IP address 192.168.1.100 wants to access a website with IP address 203.0.113.10 on the internet. The client sends the data to its default gateway, which is the router’s IP address on the same LAN (e.g., 192.168.1.1). The router then forwards the data to the internet and returns the website’s response back to the client.

A: The Layer 2 address of the switch management interface

This option is not the default gateway address. The Layer 2 address of a switch management interface is used for managing and configuring the switch itself, not for routing traffic between networks.

B: The Layer 2 address of the switch port that is connected to the workstation

This option is also not the default gateway address. The Layer 2 address of a switch port is used for local communication within the same LAN, not for routing traffic to other networks.

C: The IPv4 address of the router interface that is connected to the same LAN

This is the correct answer. The default gateway address should be set to the IPv4 address of the router interface that connects the local LAN to other networks. The router acts as the gateway for the client device to reach destinations outside of its local network.

Example: Suppose a client device with IP address 192.168.1.100 wants to access a website with IP address 203.0.113.10 on the internet. The client sends the data to its default gateway, which is the router’s IP address on the same LAN (e.g., 192.168.1.1). The router then forwards the data to the internet and returns the website’s response back to the client.

D: The IPv4 address of the router interface that is connected to the internet

This option is not the default gateway address for the client device. While the router connected to the internet may act as the gateway for the LAN, the default gateway address on the client device should be the IP address of the router’s interface connected to the same LAN, not the internet-facing interface.

Posted on

Command show ip route

Output of “show ip route” Command


Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
       a - application route
       + - replicated route, % - next hop override

Gateway of last resort is 192.168.1.1 to network 0.0.0.0

C    192.168.1.0/24 is directly connected, GigabitEthernet0/0
C    192.168.2.0/24 is directly connected, GigabitEthernet0/1
S    10.0.0.0/8 [1/0] via 192.168.1.254
S    172.16.0.0/16 [1/0] via 192.168.1.254
O    10.10.10.0/24 [110/2] via 192.168.1.253, 00:00:16, GigabitEthernet0/0
O    172.17.17.0/24 [110/3] via 192.168.2.253, 00:00:25, GigabitEthernet0/1

Output of “show ip route” Command


Gateway of last resort is 192.168.1.1 to network 0.0.0.0

This line specifies the default route, which is used when the router doesn't have a more specific route for a destination. In this example, the default route is set to 192.168.1.1 for network 0.0.0.0.


C    192.168.1.0/24 is directly connected, GigabitEthernet0/0
C    192.168.2.0/24 is directly connected, GigabitEthernet0/1

This code indicates directly connected networks. These are the networks that are directly attached to the router's interfaces. In the example, networks 192.168.1.0/24 and 192.168.2.0/24 are directly connected to GigabitEthernet0/0 and GigabitEthernet0/1, respectively.


S    10.0.0.0/8 [1/0] via 192.168.1.254
S    172.16.0.0/16 [1/0] via 192.168.1.254

This code indicates static routes. Static routes are manually configured by the network administrator. In the example, there are two static routes for networks 10.0.0.0/8 and 172.16.0.0/16. The next-hop routers for these routes are 192.168.1.254.


O    10.10.10.0/24 [110/2] via 192.168.1.253, 00:00:16, GigabitEthernet0/0
O    172.17.17.0/24 [110/3] via 192.168.2.253, 00:00:25, GigabitEthernet0/1

This code indicates OSPF-learned routes. OSPF (Open Shortest Path First) is a dynamic routing protocol. In the example, there are two OSPF-learned routes for networks 10.10.10.0/24 and 172.17.17.0/24. The next-hop routers for these routes are 192.168.1.253 and 192.168.2.253, respectively. The numbers in brackets represent the OSPF cost and administrative distance.

Imagine you have a super-smart postman called R1, who knows how to deliver letters to different houses in the neighborhood. R1 has a special map called the “Routing Table” that helps him remember all the houses and the best ways to reach them.

Directly Connected Houses (C and L):
R1 has some houses that are right next to his own house. These are the houses he can see from his window. He calls them “Directly Connected Houses.” When R1 looks at his map, he sees codes like “C” and “L” next to these houses. The “C” means they are directly connected to him, and the “L” means they are his own house. For example, R1 knows about houses 192.168.10.0/24 and 209.165.200.224/30 because they are right next to him. He knows how to reach them without asking anyone else. He even knows the best door to use to deliver letters to each house.

Learning from Neighbor Postmen (O):
R1 is not just smart; he’s also friendly! He talks to his neighbor postman called R2. They share information about the houses they know, so they can help each other deliver letters. R2 tells R1 about a house with the address 10.1.1.0/24, and R1 writes “O” next to it on his map. The “O” means he learned about this house from his friend R2 using a special language called OSPF.

Special Delivery Instructions (S*):
Sometimes, R1 gets special instructions from someone in the neighborhood. It’s like someone left a note for him on his doorstep. These special notes are called “Static Routes.” When R1 sees a code like “S*” on his map, it means he has special instructions on how to deliver letters to a specific house.

The Mystery Address (0.0.0.0):
R1 also has a special address in his map called “0.0.0.0”. It’s like a mystery address, and it means if he doesn’t know where else to deliver a letter, he can use this address as a last resort. It’s like saying, “If I don’t know where to go, I’ll go anywhere.” This special address is called the “Default Route.”

So, R1, the super-smart postman, uses his Routing Table to remember all the houses he knows, how to reach them directly, and how to ask his friends for help when needed. With this map, he can deliver letters to everyone in the neighborhood without getting lost!

Posted on

OSPF and EIGRP

Open Shortest Path First (OSPF)

Key Points:

  • OSPF is an Interior Gateway Protocol (IGP) used to exchange routing information within an autonomous system (AS).
  • It is a link-state routing protocol that calculates the shortest path to a destination based on a topology database.
  • OSPF uses the Dijkstra algorithm (Shortest Path First algorithm) to find the best path to each destination.
  • It operates using IP protocol number 89 and uses multicast addresses (224.0.0.5 and 224.0.0.6) to communicate with other OSPF routers.
  • OSPF routers exchange Link State Advertisements (LSAs) to build and maintain a consistent link-state database.
  • It supports VLSM (Variable Length Subnet Mask) and CIDR (Classless Inter-Domain Routing) for efficient IP address utilization.
  • OSPF uses cost as its metric, which is calculated based on bandwidth (higher bandwidth means lower cost).
  • It provides fast convergence as updates are triggered by changes in the network rather than regular intervals.

Enhanced Interior Gateway Routing Protocol (EIGRP)

Key Points:

  • EIGRP is a Cisco proprietary IGP that operates within an autonomous system.
  • It is a hybrid routing protocol that incorporates features of both distance-vector and link-state protocols.
  • EIGRP uses the DUAL algorithm (Diffusing Update Algorithm) to calculate the best path to a destination.
  • It uses AS (Autonomous System) to organize and control routing information.
  • EIGRP exchanges Topology Table Updates (TTUs) with neighboring routers to maintain routing information.
  • It supports VLSM (Variable Length Subnet Mask) and CIDR (Classless Inter-Domain Routing) for efficient IP address utilization.
  • EIGRP uses bandwidth and delay as its metric, providing more efficient path selection than pure hop count.
  • It provides fast convergence by using feasible successors to recover from link failures without a complete topology recalculation.
Posted on

Step in the CSMA/CA process

CSMA/CA Process for Wireless Communication

  1. The client listens for traffic on the channel.
  2. If the channel is idle, the client proceeds to send an RTS (Request to Send) message to the Access Point (AP).
  3. The Access Point (AP) responds with a CTS (Clear to Send) message to the client.
  4. After receiving the CTS, the client can proceed to send the data frame onto the wireless channel.

The RTS/CTS exchange is a key part of the CSMA/CA mechanism used to avoid packet collisions in wireless networks.

Posted on

Process that hosts use to access

Topology Type for Network Access and Communication

The topology type that describes the process hosts use to access and communicate on a network is:

C: Physical

Physical topology refers to the actual layout or arrangement of the network’s physical components, such as computers, switches, routers, cables, and other network devices.

In a physical topology, hosts use physical connections (cables, wireless links) to access and communicate on the network.

Examples of physical topologies include star, bus, ring, mesh, and hybrid topologies, each representing different ways of connecting the devices.

The other options are not related to the process of accessing and communicating on a network:

  • A: Start – Not a standard networking term or topology type.
  • B: Logical – Refers to how data flows in a network, independent of the physical layout.
  • D: Bus – Represents a specific type of physical topology where devices are connected to a single central cable.

However, the term “Physical” best describes the process of hosts accessing and communicating on the network.

Posted on

Describes the operation of CSMA/CD

Operation of CSMA/CD (Carrier Sense Multiple Access with Collision Detection)

The statement that correctly describes the operation of CSMA/CD is:

C: The end device waits until there are no data signals then transmits the data while listening for collisions.

In CSMA/CD, before an end device transmits data, it first listens to the network to detect if there are any ongoing transmissions (carrier sensing).

If the channel is idle (no data signals are detected), the device starts transmitting its data.

While the device is transmitting, it continues to listen to the network for any potential collisions.

If a collision is detected (i.e., another device starts transmitting at the same time), the device immediately stops transmitting and waits for a random backoff time before attempting to retransmit.

The process of detecting collisions and responding to them by stopping transmission and retransmitting with a backoff is the key characteristic of CSMA/CD.

It helps to manage access to the shared network medium and avoid data collisions.

Posted on

CSMA/CA that differs from CSMA/CD

CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance)

Difference from CSMA/CD: In CSMA/CA, an end device sends a notification called “Request to Send” (RTS) across the media before sending a data frame.

Before transmitting data, the device checks the channel for ongoing transmissions (carrier sensing).

If the channel is busy, it defers its transmission and waits for the channel to become idle.

Once the channel is idle, the device sends an RTS frame to the access point or receiving device to indicate its intent to transmit data.

The receiving device acknowledges the RTS by sending a “Clear to Send” (CTS) frame.

After receiving the CTS, the transmitting device can proceed to send the data frame.

This exchange of RTS and CTS helps avoid collisions in wireless networks and reduces the chances of multiple devices attempting to transmit simultaneously.

CSMA/CD (Carrier Sense Multiple Access with Collision Detection)

In CSMA/CD, there is no RTS and CTS mechanism for avoiding collisions.

Devices transmit data directly without prior notification.

Collisions, if they occur, are detected after they happen.

If a collision is detected, devices follow a backoff algorithm and retransmit data at a later time to avoid further collisions.

CSMA/CD is typically used in wired Ethernet networks.