Questions tagged [layer3]

For questions about the OSI layer-3 (network layer).

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4
votes
1answer
3k views

Help with VLANs, ACLs, DHCP on SG-300 Layer 3 switch

I have to do the following configuration on an cisco Sg-300 small business L3 switch as in the figure. Since i don’t have access to this switche for practice before doing this live in production i ...
5
votes
5answers
336 views

What blocks a computer from another network in the same switch from answering an ARP request?

Let's suppose I have 3 computers A, B and C connected to the same switch with only the native VLAN active. A and B belong to the same network, let's say that their IP addresses are 192.168.1.1/24 for ...
2
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1answer
62 views

Inter Vlan Packet Transfer

I am trying to establish communication between 2 devices within different vlan. But I require a router for that. Can I send packets within different VLAN without having a router or a Layer 3 device.
2
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3answers
2k views

What is Routing Daemon?

Reading about IP Routing, I found a brief explanation: "routing daemon, which is normally a user process. The most common daemons used on Unix systems are the programs routed and gated." In an Unix ...
2
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2answers
518 views

IP Fragmentation

When Device A sends an IP datagram toward Device B, the IP Layer of Device A computes if it must or not fragment the IP datagram to fit the link MTU. Sent to the next hop, the process will be repeated....
3
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2answers
504 views

SonicWALL TZ215 : 2 LAN interfaces and 1 WAN

Here is network schema: 192.168.2.200 - Switch layer 2 ---| |--X0 LAN 192.168.2.254 |---Switch layer 3 ---| 10.50.40.40 --- Swtich layer 2 ---| ...
2
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1answer
156 views

How do I use my SP Ethernet connection between HQ and Branch for Layer 2 and Layer 3

I am looking to use my provider Ethernet Connection between our HQ and Branch to do Layer 2 and Layer 3. The Ip addresses I hope to use for the remote are those being advertised to the ISP using BGP. ...
6
votes
1answer
4k views

Assistance with routing between layer 3 switches with ospf

I have two Cisco 3560's in a branch office. One acts as an access switch configured with two vlans: interface Vlan10 ip address 192.168.0.254 255.255.255.0 interface Vlan20 ip address 172.16.0.254 ...
2
votes
1answer
296 views

Metro Ethernet no layer 3 connectivity

We're working with a metro ethernet provider to bring up a new multi-point connection between our sites. Currently we're just trying to get it working with two sites. As a simple test I've plugged in ...
5
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1answer
309 views

Optimizing Network Topology

Recently I wish to split the network by VLANs. Mainly for two reasons Exclude management interfaces from the commonly accessible lan Separate WiFi traffic (security and broadcasts) The current idea ...
3
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1answer
11k views

Can same port configured for different IP address or different protocol

I read following line from port WIKI So, does it mean that same port, let's say 7001 can be bind to a different IP address or different protocol? As per my knowledge, it cannot be and would result ...
1
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2answers
472 views

Netgear switch required default gateway for point-to-point link [closed]

So, my Netgear switch died, and after factory resetting it, I noticed that I was unable to connect to it. The Netgear was configured for 192.168.0.239/24, and I configured my windows PC to 192.168.0....
2
votes
2answers
310 views

Does the Cisco 3560-CX support Layer 3 Etherchannel?

Does the Cisco 3560-CX support Layer 3 Etherchannel? I can see from the specs that this switch supports Layer 2 Etherchannel and that it is a layer 3 compact switch. However, it doesn't have the full ...
3
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4answers
16k views

Inter VLAN routing working, but VLANs can't access Internet

i have a question/problem. i have a local router with default-gateway 192.168.3.254, now on my layer 3 switch 3560 i configure 3 vlans. vlan 10 - data /ip address 192.168.10.254 255.255.255.0 vlan ...
1
vote
2answers
407 views

Which network protocol is used for media streaming from online music or video sites? [closed]

I would like to know which network protocols are used for media streaming by online music and video sites ?
1
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1answer
558 views

the difference in dealing of Layer 3 Switch and Router with broadcast communication

How does L3 Switch deal with broadcast communication such as ARP,DHCP or Broadcast storm? Is it the same that router deal with such as blocking a broadcast communication or ip address "255.255.255.255"...
1
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3answers
7k views

Why should I use Router on a Stick If already doing interVlan routing using L3 Switch in same netwrok? [closed]

I have this network in which the top switch(one connected to router) is used for routing between all the vlans in the network. I have defined vlan interface in this switch, but I haven't configured ...
4
votes
4answers
45k views

Intervlan routing using two Layer 3 Switches in Packet Tracer

I am having trouble when I am using two Layer 3 switches and two PCs to create a simple network for Inter Vlan routing, First of all have a look at this network, The configuration for PC1 is, IP: ...
3
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3answers
7k views

D-Link L2 & L3 Network Setup

I'm currently setting up my new network using D-Link DGS-1510 series gigabit stackable smart managed switches. It is the first time i use this L2 & L3 switches and I'm trying to setup the ...
2
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2answers
3k views

Regarding MPLS L2 Vs L3

I'm studying about MPLS Network, i've doubt on that i.e., what is the difference between MPLS Layer-2 Vs Layer-3 Network ?
-1
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2answers
848 views

Restricting IP subnets to specific VLANs (Brocade ICX)

Say I have an uplink port (1/3/1) connected to our upstream, then various clients across 1/1/1 - 1/1/48. I want to create two or more VLANs where each VLAN can only use IPs from a specific subnet. e....
0
votes
1answer
1k views

Inter VLAN - switch layer 3

I tried to configure simple topology using switch layer 3, but it doesn't work and I don't have an idea what is wrong. When I ping from 192.168.1.2 a computer 192.168.2.3 , a ICMP packet stops at ...
4
votes
3answers
5k views

Layer 2 vs Layer 3 core - with HP IRF

The SMB organization I work for is migrating to HP/3COM Comware L3 switches and we will be implementing the standard Core>Distribution>Access design. Please refer to this diagram for clarification: ...
1
vote
2answers
2k views

HP 1910 disable layer 3 mode

Is there a way i can make HP 1910 works in layer 2 mode. I check the web interface but not seeing anything Also i enable the cli and went to system view but not seeing any thing related no ip routing ...
7
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4answers
542 views

Why is the IP layer aware of higher layers in the network stack?

In the IP packet header there is an 8-bit Protocol field (at offset 9) that holds the "next level protocol", with assigned numbers given in RFC 790. For example, TCP is 6. My question is, why is the ...
3
votes
1answer
2k views

Should my layer 3 switch rewrite this MAC address?

I have the following routing table: say I get packet with dest IP 10.5.89.34 and the next hop IP is that of a logical VLANIF94 interface. please explain what all steps will happen here like MAC ...
6
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3answers
3k views

Quagga OSPF DR/BDR Mismatch: Losing Routes

I am experiencing a problem with lost routes in an OSPF over DMVPN environment. I am running ubuntu server 14.04 with Quagga 0.99.22.4, and OpenNHRP 0.14.1. While technically the DMVPN network is an ...
2
votes
1answer
471 views

How can a telecommunications carrier convert his layer 3 transmission network to layer 2 at client site?

Ok, my company has three telco providers, each telco provides data links from the central site to different remote sites. Telco provider 'A' provides layer 2 "dedicated" fiber optic links from the ...
3
votes
4answers
1k views

Should I receive an ARP reply from a host that is logically on a different subnet but is connected to my host via a hub?

Host A: 128.238.66.100/16 Host B: 128.238.67.100/24 The hosts are connected to the same hub and nothing else is connected to that hub. The routing and ARP tables of both hosts are empty. Host A ...
3
votes
2answers
9k views

Routing the same subnet in two locations / gateways?

In my current topology, I have two locations linked by a trunk. Everything on one side of the trunk is Site A, everything on the other is Site B In the example above, for 10.0.200.4 to talk to 10.0....
5
votes
3answers
438 views

Why use 'switching' term for packet switching

On a packet switching network, a router is required to route packets to different networks. Why does packet switching uses the term 'switching' when a packet is a term for a layer 3 PDU and ...
-2
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1answer
99 views

L3 switch - All L3 processing offloaded to card?

On a Cisco 3560 switch, are all L3 processing offloaded to card instead of normal CPU?
8
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4answers
33k views

Access Multiple VLANs from One Computer

I inherited a bit of mess and am preparing to redo our IP addressing scheme and also split our network into multiple VLANs. Possibly something like: 10.1.10.0/24 VLAN 10 VOIP 10.1.20.0/24 VLAN 20 ...
5
votes
2answers
560 views

Network topology suggestions?

Looking for guidance on network topology changes. Currently our network has 2 different stacks of switches running in layer 2. These switches then connect to a stack of layer 3 switches to do internal ...
5
votes
1answer
600 views

Cisco Router Multiple Interfaces in the Same Broadcast Domain

I have a Cisco 3945E with two EtherSwitch modules (gi 1/0, gi 2/0) and a UCSE (ucse 4/0) server installed in it. The short of it is i'd like to trunk VLANs to the two EtherSwitch modules, and place ...
3
votes
2answers
5k views

How does IS-IS carry IP routes?

IS-IS runs natively on layer 2 of the OSI reference model. How will the routing be done in that? My doubt is that layer 3 has the ability to do the routing. But, ISIS does not run in layer 3 rather ...
3
votes
2answers
4k views

Do MPLS LSRs require a Layer 3 IP routing protocol?

Recently I've been trying to get my head around MPLS, it's a part of the project we're doing. During one of our meetings one of the participant ask a question: Since LSRs doesn't check IP routing ...
4
votes
1answer
233 views

Hub-Spoke topology — L3 Links use multiple /30s vs single /24 shared?

I wanted to ask the community their thoguhts on the pros and cons of this scenario. I have a few L3 switches with their own independent VLANS connecting to a a set of stacked switches over a port-...
2
votes
3answers
9k views

How to assign a static IP to a Cisco Layer 3 switch in order to connect using SSH?

The steps of this manual have been executed in order to configure SSH. Once SSH has been configured, how to access the switch from a computer using SSH? The following steps have been executed in ...
4
votes
3answers
1k views

When are MAC addresses used instead of IP addresses in the OSI model?

Okay, so I'm studying for the Network+ exam, and I've gone over the OSI model about a million times, and I understand most of it fairly well, and my studies are coming along fine. However, there is ...
3
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2answers
3k views

Layer 3 Switching in Packet Tracer not working

I am studying for ICND1 through CBTNuggets, I recently watched videos on how to interact between different vlans using separate interfaces, sub-interfaces and Layer 3 Switching. The first two worked ...
4
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3answers
1k views

When is a layer 3 switch more appropriate than a router in a branch office?

It seems that as time passes, vendors have added almost all the features of a router to a layer 3 switch. For branch office deployments, how do other people who design networks choose between ...
4
votes
3answers
1k views

Difference between router leg and static routes

I am looking a L2/L3 switch spec. which says it supports 256 Router Legs and maximum of 32 Static routes. Can somebody explain with an example, what is the difference between router leg and static ...
6
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1answer
1k views

Connect Multiple VLANs which reside on same L3 Switch

Introduction The steps described in this manual have been applied in order to enable the connection between multiple VLANs which reside on the same switch. Two VLANs have been configured. VLAN 1: ...
36
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3answers
109k views

What is the difference between MSS and MTU?

I'm confused as to the difference between maximum segment size and a maximum transmission unit. Can someone please explain in relation to layers 2 and 3? If I had a packet of 800 bytes in the ...
1
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2answers
1k views

Routing Between Cisco 4507R+E Layer 3 Switch & UTM Firewall Fortigate

Please Help me. I have a Cisco Catalyst 4507R+E and UTM Firewall Fortigate and I Created VLANS on Catalyst and the main VLAN port Which Play IP Route between All VLANs can not connectet to the UTM ...
13
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6answers
11k views

How does BGP work over TCP?

As far as I know we are using routing protocols to achieve Layer 3 connectivity, I am confused with the fact that BGP works over TCP which is L4. How can L4/TCP be established without prior L3 ...
17
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6answers
59k views

What, exactly, is required to make Airplay work across VLANs? [closed]

It seems like AirPlay works out-of-the-box, vaguely speaking, only within a LAN. It's not clear to me exactly why, but it looks like at least discovery relies on broadcasts. Wikipedia states that ...
1
vote
1answer
4k views

Routing throughput of an L3 switch

The Cisco SG300-10 says its forwarding rate is 14.88Mpps with 64 byte packets. I estimated this to be ~ 7 Gb/s. Does this mean that up to 7 computers can transfer data across VLANs at full 1 Gb/s ...
4
votes
1answer
6k views

Why are there checksums for different OSI layers?

Can anyone clarify the question "why we need checksum in both layer-2 and layer-3 of OSI layer", Layer-2 would encapsulate the rest of OSI layers into a single unit. If Layer-2 has a checksum, ...