Total 46 Blogs

Created by - Stanley Avery

BPDU Guard Explained: What is it? Why do we need it?

In networking, there are a variety of important protocols that help devices communicate with each other. One such protocol is called the Spanning Tree Protocol (STP), which helps manage the flow of traffic on a network. There is an optional feature of STP called BPDU Guard, which we'll explain in this post. Let's take a closer look! Before Explaining BPDU Guard: What is the Spanning Tree Protocol (STP)? The Spanning Tree Protocol, or STP, is a network protocol that helps to prevent network loops in a switch infrastructure. Without STP, packet traffic would continually circulate through the network, causing it to crash.  STP works by creating a loop-free logical topology and selectively blocking ports to eliminate potential loop paths. This allows for redundant links in the network while preventing harmful loops from forming. STP operates at the data link layer of the OSI model and can be useful for both Ethernet and non-Ethernet networks.  In addition to STP, there are other protocols that serve similar functionality, such as Rapid Spanning Tree Protocol (RSTP) and Multiple Spanning Tree Protocol (MSTP). Understanding the basics of STP is essential before diving into topics like BPDU Guard, which builds upon and enhances the functionality of STP in certain scenarios. BPDU Guard: What is it? BPDU Guard is a security feature found in multiple networking devices. It helps to prevent attacks on a network by blocking Bridge Protocol Data Units (BPDUs) that are sent from unauthorized devices. BPDUs are used in the Spanning Tree Protocol, which helps to create a loop-free network, but they can also be used for malicious purposes.  When BPDU Guard is enabled, it will immediately disable any port that receives a BPDU, reducing the risk of attacks on the network. In order for this feature to work properly, it should only be enabled on edge ports or those that connect to external networks, as disabling BPDUs on internal ports can disrupt communication within the network itself. Generally speaking, it is recommended to enable BPDU Guard as an added layer of security for your network. BDPU Guard vs. BDPU Filter: What is the difference? The main difference between BDPU Guard and BDPU Filter is their function. BDPU Guard is a system that actively defends against malicious attacks, while BDPU Filter acts as a preventative measure by blocking unauthorized access to certain websites or networks. In simpler terms, BDPU Guard acts like a bodyguard fighting off threats, while BDPU Filter functions more like a locked door barring entry to unwanted visitors. Both approaches serve a valuable purpose in protecting against cybersecurity threats, and many businesses choose to implement both measures for maximum security. However, it's important to note that no security system is impenetrable; regular updates and monitoring are necessary to ensure the continued protection of valuable data and resources. To sum up As you can see, BPDU Guard is a powerful tool that can help protect your network from potential attacks. While it’s not a silver bullet, it’s an important part of any layered security approach. If you have questions about deploying BPDU Guard in your own environment or want to learn more about networking best practices, you must check this course to learn everything about this topic.

Published - Sat, 05 Nov 2022

Created by - Stanley Avery

IGMP Snooping: Everything You Should Know

This blog post will discuss everything you need to know about this important networking technology. We'll define IGMP snooping, explain how it works, and delve into the benefits of using it. We'll also provide some tips for implementing it in your network. So if you're ready to learn more, read on! What Is IGMP Snooping? IP multicasts are a type of network communication where a single packet is sent from a source to multiple recipients. However, in large networks, it can be inefficient for every device to receive these multicast packets, leading to unnecessary network traffic. This is where IGMP snooping comes in. IGMP snooping is a way to monitor IGMP traffic to control the delivery of IP multicast data. By keeping track of which devices have joined a specific IP multicast group, network switches can filter out unnecessary traffic and only forward the packet to the relevant recipients. This process helps optimize network performance by creating a more efficient IP multicast distribution map. Additionally, it helps reduce strain on network resources, resulting in improved overall network performance. How Does IGMP Snooping Work? IGMP snooping is a process used in networking to optimize multicast traffic. When enabled, the network switch listens for IGMP messages sent between hosts and multicast routers. This allows the switch to keep track of which hosts have joined specific multicast groups. The switch can then use this information to forward only necessary traffic to each port, reducing overall network congestion. It is important to note that it only works for IPv4 networks, as IPv6 uses a different protocol called MLD snooping. Additionally, not all devices support IGMP snooping, so it is best to check compatibility before enabling the feature on a network. What are the biggest benefits of IGMP Snooping? One of the biggest benefits of IGMP snooping is improved network efficiency. As is said before, without snooping, network switches must send out multicast traffic to every single port, even if only one or two devices are interested in receiving it. Snooping helps to identify which ports should receive the multicast traffic, reducing unnecessary network congestion. It can also help to improve response time for certain applications, such as real-time gaming and video conferencing. Additionally, it can save on bandwidth usage by allowing the switch to limit multicast traffic only to subscribed ports. Overall, implementing IGMP snooping can have a positive impact on both network performance and cost-effectiveness. IGMP Snooping Implementation Options There are two options to consider when implementing IGMP Snooping on a network. The first is the IGMP snooping querier, in which a designated device will send IGMP queries to identify members of multicast groups and maintain group membership tables. The second option is proxy reporting, where IGMP messages are relayed through a designated device instead of being sent directly from hosts. While both options can effectively reduce multicast traffic on a network, it is essential to note that some devices may not support proxy reporting. In those cases, an IGMP querier may be the preferred option. It is also worth considering the size and layout of the network when making a decision, as a larger network with multiple access layers may benefit more from utilizing a dedicated IGMP querier. Ultimately, careful planning and consideration of hardware capabilities can ensure successful implementation on any network. How to enable IGMP Snooping on a Cisco device? You can enable IGMP snooping on a Cisco drive by using these commands: switch# configure terminal switch(config)# ip igmp snooping switch(config)# vlan vlan-id switch(config-vlan)# ip igmp snooping switch(config-vlan)# ip igmp snooping explicit-tracking switch(config-vlan)# ip igmp snooping fast-leave switch(config-vlan)# ip igmp snooping last-member-query-interval seconds switch(config-vlan)# ip igmp snooping querier IP-address switch(config-vlan)# ip igmp snooping report-suppression switch(config-vlan)# ip igmp snooping mrouter interface interface switch(config-vlan)# ip igmp snooping mrouter vpc-peer-link witch(config-vlan)# ip igmp snooping static-group group-ip-addr [source source-ip-addr] interface interface Summary IGMP snooping is a process that allows routers to monitor multicast traffic on a LAN. By monitoring the traffic, routers can determine which hosts are members of a multicast group and forward multicast packets only to those hosts. This process improves network performance by reducing the amount of traffic that travels through the network unnecessarily. It should be one of your go-to tools if you’re looking for ways to improve your network’s performance.Also you can check this course about Layer 2 protocol : CCIE Enterprise Infrastructure Online Course

Published - Wed, 19 Oct 2022

Created by - Stanley Avery

Address Resolution Protocol (ARP): Everything You Should Know About

If you're like most people, you take the convenience of the internet for granted. You probably don't think about how the addresses used to route your packets to their destinations are resolved. In this blog post, we'll take a closer look at address resolution protocol (ARP), what it is, and how it works. We'll also discuss some of the security implications of ARP and ways to protect yourself against them. Stay tuned! What Is ARP? ARP (Address Resolution Protocol) is a communication protocol used for mapping a 32-bit IPv4 address to a 48-bit MAC address or the other way around. It is used on Ethernet and WiFi networks, and it is also supported by many other network types. It is a crucial part of how IP address works and is responsible for resolving address conflicts and maintaining address tables. When two devices in a network need to communicate, they first use ARP to resolve each other's address. Address resolution protocol is a part of the TCP/IP stack, and it is used by almost all modern networking devices. By understanding how it works, you can troubleshoot many networking problems. How Does ARP Work? The Address Resolution Protocol (ARP) is fundamental to Internet communication. It is used to map a network address, such as an IP address, to a physical device like a NIC. This mapping is necessary because data packets can only be sent to physical devices using their MAC address. It complements the IP protocol by providing a way to determine the MAC address of a remote device when all that is known is its IP address. When a device wants to send a packet to another device on the same network, it first looks up the destination IP address in its ARP table. An ARP table is a data structure used by network devices to store information about the mapping of IP addresses to physical MAC addresses. ARP works by sending out a broadcast message (ARP request) that contains the IP address of the target device. An ARP request is a type of packet that is used to request the Media Access Control (MAC) address of a specific computer on a local area network (LAN). The request is sent to all computers on the LAN, and the computer with the matching MAC address responds with an ARP reply packet. All devices on the network will receive this message and compare the IP address to their own. The device with the matching IP address will respond with its MAC address, which will be added to the sender's ARP cache. Now, whenever the sender needs to communicate with the target device, it can look up its MAC address in the cache and send data directly to it. This process happens automatically and is transparent to users. Thanks to this protocol, we are able to communicate seamlessly with devices on our local network without having to worry about their MAC addresses. For further information, you can read this ARP configuration guide by Cisco. Security Implications of ARP and Protection Methods Address Resolution Protocol (ARP) is a powerful tool that can be used for both legitimate and malicious purposes. When used correctly, it can help improve network performance and stability. However, it can also be exploited to execute denial-of-service attacks, insert false entries into the ARP cache, and sniff network traffic. As a result, it is essential to be aware of the potential security implications of the protocol before using it on a network. By understanding the risks associated with ARP, administrators can take steps to mitigate them and protect their networks. Denial-of-Service Attacks: A denial-of-service attack occurs when an attacker sends a large number of false ARP messages to a target device. This flooding of the ARP cache causes the target to become overloaded and unable to process legitimate traffic. As a result, the target is effectively cut off from the network. While denial-of-service attacks are generally challenging to carry out, they can be devastating in terms of their impact. The good news is that there are a number of steps you can take to protect yourself from this type of attack. First, make sure that your devices are running the latest software and security patches. Second, consider using anti-spoofing measures such as static ARP or port security. Finally, make sure that your network is segmented correctly and that those critical devices are placed on separate subnets. Taking these precautions can help ensure that your network is better protected against denial-of-service attacks. Spoofing: Spoofing allows the attacker to redirect traffic or perform other man-in-the-middle attacks. It is relatively easy to carry out and can be difficult to detect. As a result, it is a serious threat to network security. To protect against spoofing attacks, organizations should implement security measures such as port security and MAC (Media Access Control) filtering. In addition, users should be aware of the risks posed by spoofing and take steps to protect their own devices from attack. By understanding and mitigating the risks posed by spoofing, organizations can help to ensure the security of their networks. Man-in-the-Middle Attacks: A man-in-the-middle attack occurs when an attacker intercepts traffic between two victims and impersonates both victims to each other. The attacker can then read, alter, or even inject data into the communication. One way to protect yourself from man-in-the-middle attacks is to use a VPN, which encrypts your traffic and makes it more difficult for attackers to sniff or tamper with your data. You can also use a firewall to filter traffic and prevent unwanted ARP requests from reaching your computer. Finally, make sure that you have the latest security patches installed on your system to close any potential vulnerabilities that attackers could exploit. By taking these precautions, you can help to keep your data safe from man-in-the-middle attacks. Final Words ARP is an important aspect of networking that you should be aware of. You can troubleshoot networking issues, optimize your network performance, and protect yourself from several attacks by understanding how it works. Start today and check out our IT courses about ARP and more...

Published - Sun, 09 Oct 2022

Created by - Orhan Ergun

What is CDN - Content Delivery Networks?

Content Delivery Network companies replicate content caches close to a large user population. They don’t provide Internet access or transit service to the customers or ISPs but distribute the content of the content providers. Today, many Internet Service Providers started their own CDN businesses as well. An example is Level 3. Level 3 provides its CDN services from its POP locations which are spread all over the World. Content distribution networks reduce latency and increase service resilience (Content is replicated to more than one location). More popular contents are cached locally and the least popular ones can be served from the origin Why CDN - Content Delivery Networks are necessary? Before CDNs, the contents were served from the source locations which increased latency, thus reducing throughput. Contents were delivered from the central site. User requests were reaching the central site where the source was located.Figure 1 - Before CDN With CDN Technology, the Contents are distributed to the local sites. Figure 2 - After CDN   Amazon, Akamai, Limelight, Fastly, and Cloudflare are the largest CDN providers which provide services to different content providers all over the world. Also, some major content providers such as Google, Facebook, Netflix, etc. prefer to build their own CDN infrastructures and become large CDN providers. CDN providers have servers all around the world. These servers are located Inside the Service Provider networks and the Internet Exchange Points. They have thousands of servers and they serve a huge amount of Internet content. CDNs are highly distributed platforms. As mentioned before, Akamai is one of the Content Delivery Networks. The number of servers, number of countries, daily transactions, and more information about Akamai’s Content Distribution Network are as follows: 150.000 servers Located in 92 countries around the world Delivers over 2 trillion Internet interactions daily Delivers approximately 30% of all Web traffic Their customers include: All top 20 global eCommerce sites, top 30 media companies, 7 of the top 10 banks, 9 of the largest newspapers, 9 out of 10 top social media sites  

Published - Tue, 24 May 2022

Created by - Orhan Ergun

What is IP Anycast? Where it is used in networking?

What is IP Anycast? Is IP Anycast a routing protocol? Where IP Anycast is used in Networking?. In this post, I will answer these questions. I discuss these questions and often ask them in my training as well. I always receive many different answers but you will see how it is easy to understand the idea behind anycast after reading this post. IP Anycast is a way of assigning IP addresses. The same IP address is assigned to multiple nodes. It is not a routing protocol, switching protocol, or a special network design. Just a way of assigning an IP address. There are many use cases for it. Internally in the networks, Multicast uses IP Anycast for load balancing and redundancy. Specifically, PIM ASM (Protocol Independent Multicast - Any Source Multicast) uses IP Anycast for the RP (Rendezvous Point) address assignment. The same IP address is assigned on multiple nodes in the network and the underlying IGP protocol shortest path is used to determine the closest RP in a topology. IP Anycast for  CDN (Content Delivery Networks) IP Anycast is a special method for request routing in CDN architecture. Let's have a look at what is request routing and how Anycast is used in request routing. Request routing or also known as server redirection is a method to bring the customer to the optimal server in a CDN architecture.   Figure - IP Anycast vs. Unicast   In this approach, the same IP address is assigned to multiple servers located in a distributed manner. When the client sends requests to the IP address, the requests will be routed to the nearest server defined by the routing policy. With this approach content providers may lose some server selection flexibility. Consider a scenario in which Anycast forwards requests to the nearest (yet overloaded) server, by simply respecting a distance-based routing policy. CDN service providers who configure their platform with Anycast set a single IP address for all their nodes! Unlike a DNS Based CDN Redirection, where every node has a unique IP address and recursive DNS routes the client to the closest node, it uses the Border Gateway Protocol (BGP) to route clients using the natural network flow of the Internet BGP is a network-level protocol that is used by Internet edge routers to exchange routing and reachability information so that every node on the network, even though it is autonomous, knows the state of its closest network neighbors. Anycast uses this information to efficiently route traffic based on hop count ensuring the shortest traveling distance between the client and its final destination.

Published - Tue, 12 Apr 2022

Created by - Orhan Ergun

Why MPLS used? 3 things you have to know!

Why MPLS is used for?. A very common question among IT Engineers. What are the common use cases of MPLS - Multi-Protocol Label Switching?  MPLS Use Cases When it is first invented, 20+ years ago, it was considered one of the most scalable ways of doing VPNs. Faster packet processing could be achieved compared to IP destination-based routing because the IP address was 32 bits long but the Labels are just 20 bits long. But, quickly after the first invention purpose, MPLS VPNs became the most dominant reason for Networks to deploy MPLS - Multiprotocol Label Switching technology. It supported Ethernet over MPLS - EoMPLS, which is known as Point to Point Layer 2 MPLS VPN, and then soon after VPLS, which is Virtual Private Lan Service, vendors started to support. VPLS is any to any, or also known as many to many technologies. It means you can connect. your multiple sites in Layer 2 and extend IP subnet by using VPLS technology. It works based on a full mesh of Pseudowires. After Pseuodowire based Layer 2 VPNs, MPLS actual boom happened with MPLS Layer 3 VPNs. With MPLS Layer 3 VPN, which is also known as Peer-to-Peer VPN, MPLS CE, and MPLS PE, setup routing protocol neighborship and IP address prefixes are advertised from the CE to PE and between the PE as end-goal being reachability between the CE devices end-to-end. MPLS VPN PE-CE protocols should be known well by the way and we have blog posts on the website for it.MPLS Layer 2 and MPLS Layer 3 VPN has been used for the most common reason for MPLS and as of 2022, MPLS VPN is the most common use case for network owners to deploy MPLS technology. But recent years, we started to see EVPN technology and its adoption. It quickly became mature and many networks, at least for the last 5 - 6 years have been deploying it. It supports both Layer 2 and Layer 3 MPLS VPNs, though initially it was invented for the MPLS Layer 2 VPN. Other than VPNs, MPLS Traffic Engineering, Carrier Supporting Carrier, Seamless MPLS, and MPLS Transport Profile are some of the architectures, mechanisms, network administrators deploy to get the advantage of.We just provided a hyperlink, just click on the words to open a blog post about any particular technology. Don't forget, if technology doesn't come up with business benefits, we shouldn't deploy it.

Published - Mon, 11 Apr 2022

Created by - Orhan Ergun

Understanding CGN - Carrier Grade NAT

Carrier-Grade NAT (CGN) is also known as LSN (Large Scale NAT). And in my opinion, it should be called LSN since there is nothing for CGN to be a carrier-grade. It is just a NAT. With CGN, Service Providers do NAT44 on the CPE from a private address to another private address (Well known /10 prefix which is allocated by IANA) and another NAT44 on the Service Provider network. That’s why you can hear CGN, LSN, Double NAT, or NAT444. All of them refer to the same thing. Carrier-Grade NAT CGN and so many IPv6 topics are covered in great detail in my IPv6 Zero to Hero Course. But with CGN you are not enabling IPv6. CGN is a way to solve the IPv4 depletion problem in a very problematic way. Companies are also using trade-market to purchase IPv4 public addresses. The average cost per IPv4 address is around 8-10$ currently. This might increase over time. And it would be wise to expect to see much bigger DFZ space by the time because of de-aggregation. With CGN, IPv4 private addresses are shared among many customers and those shared addresses are NATed at the CGN node twice.   Difference between Customer NAT (Residential NAT) and SP NAT (CGN, LSN) With Residential NAT, a single public IPv4 address represents one household, with SP NAT (CGN, LSN), a single public IPv4 address is shared across multiple households With Residential NAT, 16-bit port space(65000 TCP and UDP ports) is for a single household but with SP NAT, 16-bit port space of the IP address is shared among multiple households. CGN can be deployed either Inline or Offline. Inline CGN deployment is more common in Enterprise and Residential networks as network traffic pass through the NAT box. Offline CGN removes the NAT from the primary data path and utilizes source routing mechanisms to send the traffic to the NAT boxes. Offline CGN is a more common deployment model in the SP networks Carrier-Grade NAT - CGN Advantages It is well known NAT, two times NAT operation, customer and SP side, no IPv6 learning curve CPE – Customer NAT doesn’t need to change CPE doesn’t need to support IPv6 Carrier-Grade NAT - CGN Disadvantages CGN is an IP address sharing solution, many users share the same Public IP address, there are problems with it Some applications break, applications that can work with a single layer of NAT may not work with two layers of NAT Sharing addresses makes operations/troubleshooting harder  How many ports should be assigned to each user? It is called Port Spray Many websites open 80-100 TCP connections (Newspapers), and some apps open hundreds of sessions (Google Map, etc.) Intense logging will be needed for the Lawful intercept Traceability of users behind Carrier-Grade NAT CGN CGN in forwarding path (Inline deployment) becomes a single point of failure Offline CGN deployment requires source routing which creates unnecessary complexity CGN IP address getting blacklisted due to address sharing (Not every user is innocent)

Published - Sun, 10 Apr 2022

Created by - Orhan Ergun

Broadband Network Architecture – Access Network Models

Broadband Network - There are many broadband services Service Providers offer to their customers today. As a network engineer, you need to know the most common services and their advantages, disadvantages, design characteristics, and so on. To have a great understanding of SP Networks, you can check my SP Workshop and also my newly published “Service Provider Networks Design and Perspective” Book. The Book covers the SP network in great detail. In this post, I will introduce these services and if I can see interest from the readers, I will explain the design aspects and deployment models of each one of them. Note: I am going to explain broadband services in this post, not baseband, we are in 2022 right?   Access network infrastructure connects the backbone network to the customers.   There are two groups of broadband access technologies. Fixed broadband technologies and Mobile Broadband technologies. You can find many Mobile Broadband articles on the website. Figure 1: Access Network Technologies and the associated infrastructures I will explain these technologies and then I will cover how physical locations can be connected to Fixed Broadband and Mobile Broadband infrastructure. Fixed Broadband Technologies Fixed broadband refers to those technologies where the end-user must remain at the same location to use the broadband service. The access network is associated with a specific physical location. Fixed broadband can be provided by wireline, wireless, or satellite technologies. Wireline Fixed Broadband Wireline fixed broadband service can be received in many ways as well. 1. DSL Fixed Wireline Broadband Traditional xDSL (ADSL, VDSL, etc.) service is one way of having fixed wireline broadband service. Today in many continents most common access network technology is DSL.   Figure 2: DSL deployment and the components   In DSL access, the traditional copper line of the telephone network is equipped with digital subscriber line technology. DSLAM is used at the Service Provider network and the customer modem connection is terminated at the DSLAM. 2. Cable Fixed Wireline Broadband The second fixed wireline broadband access technology is Cable Broadband. Broadband service is received through cable access by upgrading traditional cable television networks. Customers can receive both broadband Internet service as well as TV service over the same cable. Figure 3: Cable Broadband simplified architecture 3. Fiber Fixed Wireline Broadband The third and last fixed broadband access technology is Fiber. You probably heard FTTx before. There are many deployment options for FTTX access for sure. You may have heard FTTH (Fiber to the home), FTTP (Fiber to the Premise), FTTB (Fiber to the Building), and so on. Figure 4: Different FTTx Deployment Options Fiber access infrastructure is different from DSL and Cable in many ways. With Fiber to the Home, from the fiber termination device of the Service Provider up to the modem in the customer's home, the entire access network is fiber. This is the fastest option customer can get. As you might know, finer has much less attenuation and loss compared to copper and coaxial cable. Much higher data rates can be achievable through fiber. (In theory, you can send 300.000km/s over fiber, because the limit is the speed of light). Between the customer and the street cabinet can be copper-based and DSLAM can be located on the street. DSLAM to the fiber termination device which is located at the Service Provider Telephone Exchange (In the U.S it is generally called CO (Central Office) ) can be fiber. This is another way of deploying FTTx service and called Fiber to the Premises/Cabinet or Curb. In the above figure, the third deployment model which is Fiber to the Building is shown. In this deployment option, fiber is brought up to the building and between DSLAM and the customer modem, the connection is copper-based. Wireless Fixed Broadband The most common technology for fixed wireless is WiMAX (Worldwide Interoperability for Microwave Access). Microwave access is much cheaper compare to fiber access for wireless access operators. Fiber access infrastructure can be leased from the fiber infrastructure providers by the wireless operator (This is very common among the Mobile Service Providers) or the wireless operators can deploy their own fiber infrastructure. In both methods, capital expenditure is higher compared to wireless-based access systems. Thus, today's most common wireless backhaul is deployed via microwave as you can see from the below picture as well.   Figure 5: Fixed Wireless Network With WiMAX, access speed can reach up to 1Gbps and the customer connection speeds depend on the distance from the wireless base station. Satellite Fixed Broadband Satellite connections are generally used in rural areas where there are no other access network options available. By the way, when you work in the Network Operator or Service Provider environment, especially if you are doing any kind of capacity planning work (Transport, Access, or IP network), you always hear urban, sub-urban, metro, and rural areas. These are related to the number of people per square kilometer. If the area is so crowded (Generally 4000 people/ sq km) it is called metro, after metro, urban, then sub-urban, least crowded places are called rural areas. Satellite connection has much higher latency compared to other fixed broadband access technologies. Speed increases by reducing latency, increasing bandwidth doesn’t mean faster connection. This is another long discussion probably we should make. When people increase their bandwidth, they tend to say we have a faster connection. That's completely wrong. When you have a shortcut (so lower latency ) you have a faster connection. satellite connection   Figure 6: Satellite Communication Last but not least, satellite connection is almost always more expensive for the same speed, compared to other fixed broadband access technologies. Mobile Broadband Mobile broadband refers to those technologies where the end-user can use the broadband service while on the move and from any physical location. These technologies provide different service speeds to the customers and the Service Provider access and the backbone infrastructure is designed in a completely different way.     Figure 7: Different mobile broadband connection speeds As I told you in the beginning, we have many mobile broadband technology posts on the website and you can watch the Mobile Broadband Technologies webinar which I did with one of the mobile broadband experts worldwide earlier this year. Fixed broadband technologies due to technical and financial aspects, tend to be prevalent in highly populated areas (Metro, Urban ) and mobile broadband technologies are more prevalent in less densely populated places. (Rural areas). If you liked this post, share it on social media and put a comment in the comment box below so I know that there is an interest in these technologies among my readers.

Published - Sun, 10 Apr 2022

Created by - Orhan Ergun

Unicast Multicast Broadcast Anycast and Incast Traffic Types

Unicast Multicast Broadcast Anycast and Incast Traffic Types will be explained in this post. Traffic flow/traffic types are important information that needs to be considered in Network Design, thus understanding each one of them by every IT Engineer is critical and Important for Application requirements, Security, and Performance of the overall system. In this blog post, Unicast, Multicast, Broadcast, and Anycast traffic types/patterns will be explained with examples and the topologies. Unicast Traffic Flow Unicast traffic type is a point-to-point communication type. Usually from a scalability perspective, Unicast is not the desired traffic type. But if there are only two points that communicate with each other, Unicast is an optimal choice. Multicast Traffic Flow Point to Multipoint or Multi-Point to Multi-Point Traffic type. If the communication is targeted to a group of recipients, then the Multicast traffic type is more suitable. Multicast source/sender, receivers, and multicast groups are the components of Multicast communication. A classical example is IPTV - IP Television. One multicast group is assigned for each IPTV channel and only interested receivers get the stream. Broadcast Traffic Flow If traffic is sent to everyone, regardless of considering if there is an uninterested receiver, then it is a broadcast traffic type. ARP traffic is a classical example of Broadcast traffic type. ARP - Address Resolution Protocol packets are sent to the broadcast address and every receiver has to process it, even if the packet is not targeted for them. If there are many uninterested receivers, Broadcast traffic is considered inefficient. Anycast Traffic Flow Anycast is a way of deploying an IP address. The same IP with the same subnet mask is assigned to multiple devices and whichever other devices need to communicate with this IP address, send the traffic to the topologically (IGP/BGP cost) closest point. Classical examples are, Anycast DNS such as Google DNS or Multicast Anycast RP (Rendezvous Point). Incast Traffic Flow If the traffic type is Multipoint to Point, it is called Incast. Big Data type of traffic requires many servers to process the same data and send the output to another engine. So multiple servers compute the information and send it to the receiver at once. Network design is so critical as there might be bottlenecks easily in this type of traffic. Unicast vs Multicast The difference between unicast and multicast, as mentioned before, if there are multiple receivers, sending traffic as unicast would be inefficient. If the packet is sent only once from the source, and the network can replicate it, less effort is spent on the source, and less bandwidth is used on the network. Let's have. a look at the below example: There is one sender/source but 3 receivers, so in Unicast's case, the same data needs to be sent 3 times. In Multicast communication, the sender/source sends the data only 1 time, network devices replicate the traffic, and 3 receivers get the same data. Obviously, this is more optimal for the sender and network resources, because of less resource usage. These resources usually are CPU, Memory, and Network Bandwidth. Multicast vs Anycast Multicast traffic is sent to many receivers at the same time. So, the source/sender sends one copy and it can be sent to hundreds, if not thousands of receivers, and all receivers get it. Anycast on the other side, one copy is sent and there is one receiver as well. But if that receiver fails, there is another receiver with the same IP and same subnet mask in the network and it receives it. So, with anycast target/receiver is always more than one. In the Google DNS case, with the same IP address, there are tens of DNS servers around the world. If traffic comes from France, the France DNS server replies, if it comes from London, London DNS replies, and so on. Closest receiver/target replies. Multicast vs Broadcast An important difference between Multicast and Broadcast is, that with Multicast we send the traffic to the interested receivers. With broadcast we don't care if there is interested people or not, it is sent everywhere continuously. There is Multicast PIM Dense mode, for example, you might compare it with Broadcast. They can be seen as similar but they are not. With PIM Dense, we send the traffic everywhere initially but if there are no interested receivers at the same Multicast enabled locations, the sender stops sending to those locations because the sender receives Multicast Prune messages. With broadcast, no Prune mechanism, thus traffic is sent continuously even if there is no interested receiver. Unicast vs Multicast vs Broadcast vs Anycast When you see this comparison again, just remember, if it is only two-party for communication, Unicast is an optimal choice. If there are multiple, look at if some of them are interested to hear some discussion, others might be interested in other discussions, then Multicast is the best. If there is only one type of discussion and everyone should receive it, the broadcast is the optimal choice. Let's say a group of people in a party some of them talk about politics, other groups of people discuss religion, and so on. So this is Multicast communication. But if someone in that party loudly starts shouting and everyone has to hear even if they are uninterested, he is broadcasting. In a summary: Unicast is one-to-one, Multicast is One to Many, Broadcast is One to All, Anycast is One to Any and Incast is Many to One communication models.  Source:  

Published - Sat, 09 Apr 2022