Router vs Switch layer3

Khan Mohammad Habibi

Nov 20 , 2016

Contents

1 abstract ii

2 introduction 1

3 Method 2

4 Result 34.1 What is the difference between a Layer-3 switch and a Router? 64.2 Why we need a Layer 3 switch: . . . . . . . . . . . . . . . . . 64.3 Difference between a Layer-3 switch and a Router: . . . . . . . 8

4.3.1 Performance versus Cost . . . . . . . . . . . . . . . . . 84.3.2 Port density . . . . . . . . . . . . . . . . . . . . . . . . 84.3.3 Flexibility . . . . . . . . . . . . . . . . . . . . . . . . . 8

4.4 Compression between router and switch L 3/2 protocols . . . . 94.5 Security on router and switches . . . . . . . . . . . . . . . . . 12

5 Discussion 145.1 Switch layer 3 and router have the same security features like 15

6 References 17

i

1 abstract

In this paper we introduce some important issues about the usages of switchlayer 3 and router and their capabilities. We discus on differences betweenthese two layer 3 devices, and what caused to use switch in layer 3. Wesearched in internet about my topic and thesis statement to find a good so-lution. And we found my response.

Ultimately we find that router has better capabilities and more usages thanswitch layer 3, but we need both of them if we want to have a good networkingand internet connection in our organization.

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2 introduction

Routers and switches are both computer networking devices that allow oneor more computers to be connected to other computers or to other networks,(Router vs. Switch, 2016).

Routers determine the paths according to sender and receiver IP addresses,but switches determine the paths according to sender and receiver MAC(Physical address) addresses. Switch layer 3 in fact a layer 2 device thathas some routing (layer 3) capabilities, and router is only layer 3 device thatperform routing (Yejian Technologies, 2011).

In this topic we discuss about Switch layer 3 and router, and the reasonwhat is needed to the Switch layer 3 when we have router in the layer 3 ofOSI model. We searched in the internet to find the reasons of using switchlayer 3 in the layer 3 of OSI model, and evaluate them with router. Thisresearch never done before in Herat University.

Also in this topic we evaluate the capability, speed, use of protocols, security,and performance between switch layer 3 and router which are collected orpresented in the result, and we will discuss in the discussion.

Ultimately we find that router has better capabilities and more usages thanswitch layer 3, but we need both of them if we want to have a good networkingand internet connection in our organization.

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3 Method

We search and collect information about my research in the internet to eval-uate between router and switch layer 3 and we ask some questions from myteacher ”Vakili”, about my research, and also we search about my thesisstatement in the internet for more information and better help.

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4 Result

The general differ between Switch layer 3 and Router is that the Switchlayer 3 works very fast like switch layer 2 because they have ” optimizedhardware”, to transfer data as soon as they receive, and Switch layer 3 knowhow to forward traffic at layer3 like a Router. ” In fact, many of CiscosLayer 3 switches are actually routers that operate faster [In a LAN] becausethey are built on switching hardware with customized chips inside the box”,(Yejian Technologies, 2011).

In switches we have Link Aggregation, we can aggregate multiple physicallinks into one logical link, in switches only links which are same in speed,duplex, access, trunk, VLAN Number, Native VLAN can aggregate whiteeach other. Aggregations increase the bandwidth. In routers we have loadbalancing in which we can aggregate the links that are not same by EIGRPprotocol.

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Table 1: Router vs Switch Layer 3

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Table 2: Router vs Switch Layer 3

(Router vs. Switch, 2016).

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4.1 What is the difference between a Layer-3 switchand a Router?

A Layer 3 switch works much like a router because it has the same IP routingtable for lookups and it forms a broadcast domain. However, the switch partof Layer 3 switch is there because:1. The layer 3 switch looks like a switch. It has 24+ Ethernet ports and noWAN interfaces.2. The layer 3 switch will act like a switch when it is connecting devices thatare on the same network.3. The layer 3 switch is the same as a switch with the routers IP routingintelligence built in.4. The switch works very quickly to switch or route the packets it is sent.

Layer 3 Switch is really like a High-Speed Router without the WAN connec-tivity. When it comes to Layer 3 Switching, there are two kinds: hardwareand software. With a hardware-based solution, the device is using an ASIC(Application Specific Integrated Circuits) A Dedicated Chip, to perform thefunction. With the software implementation, the device is using a computerprocessor and software to perform the function. Generally, Layer 3 Switchesand High-End Routers route packets using Hardware (Asics) and General-Purpose Routers Use Software to Perform Routing Functions.In General, A Layer-3 Switch (Routing Switch) Is Primarily a Switch (ALayer-2 Device) That Has Been Enhanced or Taught Some Routing (Layer3) Capabilities. A Router Is a Layer-3 Device That Simply Do RoutingOnly. In The Case of a Switching Router, It Is Primarily A Router ThatUses Switching Technology (High-Speed Asics) For Speed And Performance(As Well As Also Supporting Layer-2 Bridging Functions).

4.2 Why we need a Layer 3 switch:

1. Network with a lot of broadcasts that needs better performance.2. Subnets and/or VLANs that are currently connected Via a router.3. Higher Performance VLANs.4. Departments Need Their Own Broadcast Domains for Performance orSecurity.5. Considering Implementing VLANs.

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Fig 1: Inter VLAN routing by switch layer3 and connecting to WAN byrouter.

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4.3 Difference between a Layer-3 switch and a Router:

4.3.1 Performance versus Cost

Layer 3 switches are much more cost effective than routers for delivering high-speed inter-VLAN routing. High performance routers are typically muchmore expensive than Layer 3 switches.

4.3.2 Port density

Layer 3 switches are enhanced Layer 2 switches and, hence, have the samehigh port densities that Layer 2 switches have. Routers on the other handtypically have a much lower port density.

4.3.3 Flexibility

Layer 3 switches allow you to mix and match Layer 2 and Layer 3 switching,meaning you can configure a Layer 3 switch to operate as a normal Layer 2switch, or enable Layer 3 switching as required.

Layer 3 Switch is used to route traffic between Ethernet networks, withouthaving to worry about the complexities of supporting WAN technologies suchas Frame Relay or ATM. Routing over WAN networks, simply by plugging atraditional router that connects to the WAN networks into the LAN network(What is the difference between a Layer-3 switch and a Router, 2016).

Totally we have two types of Routing protocols: All routing protocols whichwe discuss and define their types supported by switch layer 3 and router.

Static Routing protocol in which the paths defined by users. Dynamicrouting protocols in which the paths defined by routing protocols and dy-namic routing protocols divided into following parts (Cisco Networking Academy,2014).

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Fig 2: Routing Protocol Classification.(Cisco Networking Academy, 2014).

4.4 Compression between router and switch L 3/2 pro-tocols

List of all protocols which are supported by router and switch layer 2/3,shown by table:

Table 3: Compression between router and switch L 3/2 protocols.

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Table 4: Compression between router and switch L 3/2 protocols .

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4.5 Security on router and switches

List of all security measure which are implemented on router and switch layer3, shown by table:

Table 5: Some essential materials to have a secure router.

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Table 6: Some essential materials to have a secure Switch.

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5 Discussion

Switches layer 3 is faster than a router in a LAN environment because theyuse hardware and software for forwarding data, first time they use softwareto forward the first packet which receive after that all packets are switchedas soon as they received, but routers always do forwarding with software,and routers are faster than switch layer 3 in MAN WAN environment.In switches we have aggregation, we aggregate multiple physical links intoone logical link which same to increase the bandwidth, but in routers we haveload balancing, we can aggregate the links which are not same. Switches layer3 can connect more computers to gather and also can pass data between net-works, but routers can pass data between networks and modems.

Switch layer 3 can operate in layer 2/3 of OSI model and router only canoperate in layer 3 of OSI model. Switch layer 3 transmit the data in theform of packet (switch layer 3) frame (switch layer 2), but router transmitonly in the form of packet. Switch first broad cast; then unicast multicastas needed the data, but router initial broad cast; then unicast multicast.

Switch layer 3 has multiple ports 24/48/64, but router has 2/4/8 ports.Switch layer 3 is active device and networking device, it works only in LAN,but router is networking device, it works in LAN, MAN, WAN and it connectLAN with WAN. Switch layer 3 transmission mode is half/full duplex andit has one broadcast domain (unless VLAN implementation), but router usealways full duplex and every ports has its own broadcast domain.

Both of them intelligent devices. Switch layer 3/2 do not share the bandwidth, but router can share bind width (dynamic or static) between inter-faces. The speed of switch layer 3 is 10/100 Mbps 1Gbps, but the speed ofrouters 1-10 Mbps (wireless) 100 Mbps (wired).

Switch layer 3 take more time for complicated routing decisions, andswitches cannot perform NAT, but router take faster routing decisions, andperform NAT. Switch layer 3 use MAC address in L2 and IP address in l3, butrouter use IP address. Switch layer 3 act like a switch layer 2 when connectthe devices which are in the same network and it support layer 2 functionsalso it has same routing capabilities and a routing table like a router. Switchlayer 3 support VLANs and inter VLAN routings, when we create VLANs

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we make our network more manageable and secure, each departments has itsown broadcast domain and better speed and performance, but routers onlydo inter VLAN routing. Layer 3 switches are much more cost effective thanrouters for delivering high-speed inter-VLAN routing. High performancerouters are typically much more expensive than Layer 3 switches.

Layer 3 switches allow you to mix and match Layer 2 and Layer 3 config-urations to perform all two layer operations, but router only support layer 3configuration. Switch layer 3 support some routing protocols like: and donot support routing protocols like EIGRP and BGP because we said beforethat switch layer 3 support aggregation feature, but not support load balanc-ing and EIGRP is the only protocol that support load balancing. And alsoswitch layer 3 not support MAN/WAN interface, and BGP is the protocolthat used between ISPs and connect ISPs to gather. Switch layer 3 supportall layer 2 protocols, but router support all layer 3 and routing protocols

5.1 Switch layer 3 and router have the same securityfeatures like

1. Console password = for login password to the console.2. VTY password = password for telnet and SSH3. Enable password = Prevent someone for full access to router4. Enable secret = Same to enable password but it is encrypted

But switch layer 3 has another security feature like:1. Port Security with MAC address = that limit users access to the networkusing MAC address .Also router has another security feature like:1. Using ACL with firewall = ACLs are typically used for protect Routersfrom attack. Besides ACLs using firewall will be much better than just usingACLs.2. And Aux Password = For auxiliary port.Bothe switch layer 3 and router support all routing protocols.

Switch layer 3 used in LANs, because it is very fast in a LAN and chip-per than router. We can create VLANs on switch L3 and do inter VLANrouting; by the inter VLAN routing we decrease the broad cast domain, but

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switch L3 cannot support NAT, WAN interface, ACL and etc (other layer 3protocols). Router support NAT, WAN interface, ALC, and etc (other layer3 protocols). Without router we cannot connect to internet. Router has morecapabilities than switch layer 3 like: Supporting Load balancing (b/w samedifferent links) to increase band width, taking fast routing decision, moresecurity, limiting the broad cast domain, faster in WANMAN environment;and work in LAN, MAN WAN.

Ultimately we find that router has better capabilities and more usages thanswitch layer 3, but we need both of them if we want to have a good networkingand internet connection in our organization.

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6 References

Cisco Networking Academy. (Mar 24, 2014). Cisco Networking Academy’sIntroduction to Routing Dynamically. Page 1.Retrieved from http://www.ciscopress.com/articles/article.asp?p=2180210seqNum=7I take it in: 6 November, 2016

OSI Layers Protocols. (OSI Layers Protocols, August 2015). List of net-work protocols (OSI model). Page 1.Retrieved from https://en.wikipedia.org/wiki/Listofnetworkprotocols(OSImodel)Itakeitin : 6November, 2016.

Routervs.Switch.(2016).Routervs.Switch.Page1.Retrievedfromhttp : //www.diffen.com/difference/RoutervsSwitchItakeitin : 5November, 2016.

What is the difference between a Layer-3 switch and a Router (31 Octo-ber, 2016). What is the difference between a Layer-3 switch and a Router.Page (1-3).Retrieved from http://rumyittips.com/what-is-the-difference-between-a-layer-3-switch-and-a-router/I take it in: 7 November 2016

Yejian Technologies. (2 December, 2011). Router vs. Layer 3 Switches.Page 1.Retrieved from http://blog.router-switch.com/2011/12/discussion-router-vs-layer-3-switches/I take it in: 5 November, 2016.

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