Questions tagged [layer3]
For questions about the OSI layer-3 (network layer).
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2answers
25 views
Is static routing used in large networks?
I'm a beginner in networking stuff and just wondered if Static Routing has any use in large networks ? How about small ones ?
In which cases we prefer to use static over dynamic routing ?
I searched ...
2
votes
1answer
61 views
MAC Table vs ARP
I understand that for a switch to learn a MAC address, if host A wanted to send data to Host B the switch learns host A MAC and places it in the MAC table. If it doesn't know where the MAC (for Host B)...
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1answer
38 views
Successful Intervlan Routing on a Layer 3 Switch, Unsuccessful IP Routing
Hello and thank you in advance for your help!
I'm using Packet Tracer for testing purposes and I' m trying to implement a simple intervlan routing in a Layer 3 Switch (3560-24PS) and an IP Routing.
...
3
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3answers
85 views
Is it possible to perform a Layer 2 (MAC address) traceroute?
I understand the difference between layer2 & layer3 and MAC & IP. I understand address resolution protocol, etc. But is there any way to do a traceroute that will show Layer 2 information? For ...
2
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3answers
425 views
Does a router send frames or packets?
Perhaps it's a novice question, but does a router send/receive frames?
When I read about this subject, it seems that routers decapsulate the frame on arrival, and encapsulate the packet in a frame in ...
2
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2answers
80 views
Mgmt Vlan vs other SVI s
Think of a layer 3 switch. Assume that we have a management vlan and a mgmt vlan interface. And we have other svi's on the switch. The question is this. I know that mgmt vlan is for telnet/ssh, simply ...
3
votes
1answer
140 views
Cisco ARP cache rewrites?
I know that the Cisco's default ARP entry expiration is 240 minutes, however how does the ARP table mechanism work when a different MAC address is seen using the same IP?
In other words, if I move ...
2
votes
1answer
43 views
Is it worth the effort to split up in layer 3 with point to point links? [closed]
I have this technical question.
With my family we have a little business. I got to provide internet access to three places, separated a few hundred meters each other. I need to allow to watch the ...
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1answer
29 views
HP 2920 Routing
I am working on setting up routing on a HP 2920 to a firewall. I can not figure out what I need to do to get this set up. I know that the ip routing command turns on routing and the ip route ...
0
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0answers
18 views
How can I convert a switchport virtual interface to layer3 interface in ONS?
I use this Networking System(ONS):
I help interface, get bellow information:
there are mgmt-ethernet, port-channel, and range.
In the port-channel I add a virtual interface 3801, but how can I ...
1
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2answers
30 views
How can subnets not fulfil symmetric property?
While studying Internet Protocol, I came upon the following example of two devices:
Device A:
IP address: 10.1.1.1
Subnet mask: 255.255.255.0
and
Device B:
IP address 10.1.1.200
Subnet mask 255....
1
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1answer
157 views
Firewall on a stick for Intranet and static routing
I have a question about possible problems that can occur with this network design.
If I have an intranet with a firewall on a stick design, multiple switches with layer 2+, is this setup fine? or ...
1
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1answer
122 views
Help with small office setup - Cisco SG350 28 port switch
I have very limited knowledge in Cisco IOS but in a crucial state to setup up a small office network. I have bought 2 Cisco SG350 28 port Layer 3 switch,
Switches should be enabled with VLAN and VTP.
...
3
votes
2answers
163 views
L2 / L3 on CISCO ASR
I am new to CISCO and have the following problem:
I have 3 routers. Between these only one physical connection.
The VLAN 100 is connected to R1 and R2.
The VLAN 200 is connected to R1, R2 and R3.
The ...
2
votes
1answer
80 views
Connect two VLANs on an NE1032 Lenovo L3 Switch
I just got a new Lenovo ThinkSwitch NE1032 with some 1G sfp. I have already created two VLANs called FE and BE that have the following IDs: 2,3. I have managed to assign an IP subnet to both of them, ...
4
votes
1answer
215 views
Cisco 3172 asks for LAN_ENTERPRISE_SERVICES_PKG license to enable OSPF and PIM when they are LAN_BASE_SERVICES_PKG license features
I have several Nexus 3100 switches in which I use OSPF and PIM. Cisco says that these features are included in the LAN_BASE_SERVICES_PKG which is included by default in the switches.
Switch1# sh ...
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4answers
1k views
Do layer 3 protocols use layer 2 protocols?
I saw the STP on layer 2. The guy that made the tutorial says at the end :
Even though it seems that Layer 2 access layer solutions are slowly
being replaced by blazing fast Layer 3 solutions.
...
1
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2answers
127 views
Inter vlan routing not working
Apologies if any details not clear as I'm not a network expert.
I have a Procurve 3500yl layer-3 switch. I am trying to make two VLANs and get a PC in one VLAN to connect to the other VLAN.
Below is ...
2
votes
1answer
187 views
Is There an Indication in Protocol Stack showing that the End Host is Mobile?
Suppose you are using the Web from your mobile phone. Is there any indication in the internet backbone, when you look at the traffic that shows that the end host is a mobile device?
I am sure there ...
1
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1answer
37 views
Unable to reach a device on another net while having routes
I'm not sure what I'm doing wrong and would therefore need some guidance. The goal is to be able to have a SSH connection between:
PC -> C
On PC I have created a route
route add 192.168.50.0 mask ...
2
votes
1answer
85 views
TCP connection question
Let’s say I have 4 ethernet interfaces getting IP addresses via DHCP.
I make a TCP connection to a TCP server via one of the IP addresses on a certain ethernet interface. After the connection is ...
1
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2answers
191 views
BGP with x2 sessions and x2 L3 VLANs - Please Explain
I am learning about Cisco BGP networking now and came across an interesting situation. In my examples, there was one which suggested that two VLANs were configured on Layer 3 in order to run two BGP ...
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3answers
106 views
Why do clients request a MAC via ARP, if the router knows the local LAN's MAC addresses already?
If I have an infrastructure type network, why does a local PC send out an ARP request for a MAC? Doesn't the router know the MAC addresses already, since it is using at least Layer 2?
Does it do ...
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2answers
130 views
Routing specific TCP/UDP packets from VLAN's to proxy server
I need to set up a solution which is for routing specific TCP/UDP packets between the devices in two separate VLANs through a proxy server. For eg: all my computers are connected to one VLAN(1) and my ...
2
votes
2answers
337 views
Connecting Layer 2 switchport to layer 3 port
I have a config that I am trying to bring up, and in my mind it should work, but perhaps I am missing something.
The idea is that one end of the link is a layer 3 interface on a router. The other end ...
1
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1answer
33 views
Separate network for test systems
I often read that you should put customer machines into a separate (testing) network like a DMZ.
Is a layer 3 device (switch/router + firewall) a good option for this? Since some ports need to be ...
3
votes
5answers
435 views
Is there a Layer 2 address advertising protocol?
I needed help in understanding if LLDP/CDP is the Layer 2 equivalent to RIP or say any Layer 3 route advertising protocol. If not,is there a protocol that advertises the MAC Address Tables among ...
1
vote
1answer
300 views
Routing and Bridging on a Layer 2 or Layer 3 device
The thing that intrigues me is, say I have a router and I configure it’s interface as a Layer 2 and have 2 Vlans on the same router. So if I want to transfer the data from one Vlan(say VLAN-10) to ...
0
votes
1answer
51 views
Routers and RIP violation of isolation?
I'm studying networking from the book 'A top down approach' from Kurose and Ross.
In the book it is stated that routers are generally considered Layer 3 devices (i.e. implementing the stack up to ...
2
votes
1answer
608 views
At which layer does router operate?
I have studied from various sources that router is a layer 3 device. It does routing based on Network layer (layer 3) header, but I have a doubt.
Network address translation (NAT) is a feature of ...
4
votes
1answer
69 views
How does Junos distinguish that route is learned in Layer 3 or Layer 2 VPN environment?
As I understand from Understanding Junos OS Routing Tables document, then bgp.l3vpn.0/bgp.l3vpn-inet6.0 or bgp.l2vpn.0 tables contain routes learned from other PE routers in Layer 3 or Layer 2 VPN ...
2
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1answer
108 views
Weird networking behavior with a gateway between a switch and CMC module, on Dell VRTX equipment. Am I doing something wrong?
Diagram:
Here's the simplest way I know how to explain how the internal networking of this Dell VRTX works.
So, you have your 4 blades and your network switch module that have integrated remote ...
5
votes
3answers
7k views
What are the reasons for seeing an incomplete ARP?
As was mentioned in this post:
The reason for seeing an incomplete ARP is that "An ARP request was sent for that address, but the host with that address is not up and running on the LAN, so there is ...
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1answer
374 views
Bridging networks without NAT: how it's done?
I have quite limited networking experience, so probably i'm asking about very simple things. I'm reading about linux bridge interfaces, and documentation states that there is no NAT by default and ...
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2answers
104 views
1 Layer 3 Switch, 2 Vlans, 2 Subnets, and an Unmanaged Switch
Is it possible to for a device with the ip address 192.168.0.1 and Vlan 100 to communicate with an other device with the ip address 192.168.1.1 and Vlan 200 with the following architectures
Senario 1:...
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3answers
1k views
When is 'Timestamp' and 'Timestamp Reply' are used in ICMP protocol?
I started the packet capture in my laptop through Wireshark application.
Now through cmd, I pinged some server (say, www.google.com).
And i stopped packet capture and analysed the packets being ...
2
votes
2answers
240 views
Routing steps on a serial port
"Because the exit interface is not an Ethernet network, R2 does not have to resolve the next-hop IPv4 address with a destination MAC address."
- this is routing from serial port , can anyone explain ...
0
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1answer
401 views
how to do intervlan routing between two hosts in different subnet
how to do intervlan routing between two hosts in different subnet separated by two layer 3 switches & without using ip routing command & by using the concept of native vlan.
3
votes
3answers
270 views
Layer 3 tunnel with Dynamic IP address
I want to ask whether it is possible to configure Layer 3 Tunnel with the two end points/interfaces have dynamic IP address?
If the interface IP change, the tunnel will have to be re-negotiated, is ...
5
votes
5answers
1k views
Why can't two hosts (in two different logical networks) connected to each other through cross-over cable communicate?
Let us say, i have two computers (hosts) A and B. Where A has been assigned an IP address of 192.168.1.10/24 and host B has been assigned an IP address of 192.168.2.11/24.
And both of them has been ...
-1
votes
1answer
374 views
How to implement Layer 3 (OSPF, IS-IS) link redundancy?
I think this kind of topic may be a course basic, but I'm still have a lot of technical doubts on how to implement redundant links on Layer 3, for example:
-In order to use dual homing for a remote ...
2
votes
1answer
503 views
SD-WAN vs MPLS VPN
Citing wikipedia on MPLS VPN
There are three types of MPLS VPNs deployed in networks today: 1.
Point-to-point (Pseudowire) 2. Layer 2 (VPLS) 3. Layer 3 (VPRN)
I am confused about the difference ...
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vote
2answers
190 views
CGN and its advantages
I have been reading about CGN. Though similar to NAT it is used by service providers to route traffic without the need for the a public IP address.
But when the packet leaves the ISP to the public ...
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1answer
123 views
Two Layer 3 Switches to one router
So I have a cisco 2811 router and 2 3560 switches
Currently the router is connected to Core1 only, what i would like to do is use the other port on the router (fa0/1) to connect to Core 2.
How do I ...
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1answer
41 views
Catalyst InterVLAN Routing w/ Failover ASAs
I currently have interVLAN routing configured on my Catalyst 3750. My gateway of last resort is my ASA firewall. The switch reaches the firewall through a layer 3 port. The port is configured as ...
4
votes
3answers
564 views
How does a router a layer 3 device translate port address in PAT, as it is a layer 3 device?
While I was reading about PAT i.e Port Address Translation.The router was configured to translate all the private IP addresses to one single public IP.Since router is a layer-3 device, it can do that ...
3
votes
2answers
4k views
How to trunk VLANs over Layer 3 EtherChannel?
I am trying to setup a network that includes an EtherChannel link between two Cisco Layer 3 switches (Catalyst 3750). I am using a collapsed core hierarchical network.
The picture above is my ...
2
votes
1answer
247 views
INTER-VLAN Routing with different Internet Access for each vlan
I have a situation that needs some clarification.
I have three sites (1,2,3). The core switch do Inter-vlan routing. Site 1 and 2 must access the internet via ISP1, while site 3 will access internet ...
0
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1answer
77 views
How to extend ports with L3 switch or other device? [closed]
I am a software engineer and no one in my team is familiar with network setup. My team recently bought 20 PCs for test our software but we only have 2 ports left in the room. And I have suddenly come ...
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1answer
1k views
Router vs VLAN in networking?
Why do we need Routers at all when we have VLAN ?
Vlan breaks the broadcast domain.
Vlan along with the use of SVI can be used for routing.
So why do we need routers for in networking ?
