Questions tagged [layer3]
For questions about the OSI layer-3 (network layer).
233
questions
0
votes
0answers
22 views
Can Northbound interfaces (REST API) in a Software Defined Network (SDN) be used to manipulate QoS parameters?
I am working on a project involving Quality of Service (QoS) manipulation in Software Defined Networks (SDNs). I know that the following parameters affect the QoS in an SDN:
Time information (inter-...
1
vote
1answer
32 views
2 machines can have the same link-local address, in the correct context. What context?
I don't get in what context multiple interfaces/machines can have the same link-local address. Thanks in advance.
-1
votes
0answers
23 views
Allied Telesis “no switchport” Cisco command [closed]
I am trying to use an Allied Telesis L3 Switch to route multiple vlans. I used to run the "no switchport" command on a L3 Cisco switch to make the interface Layer 3 capable. Whenever I run the "no ...
2
votes
1answer
38 views
Query on PTP Transparent Clock
I had a query in PTP Transparent Clock(TC), Please consider the below picture for my question.
I will try to express my question with the help of a real world example
Say, two places Place_A <----...
0
votes
2answers
54 views
Unicast to Multicast possible?
could I check if it is possible to convert TCP traffic to UDP multicast and if there are any appliances / switches that can do so?
E.g. Workstations A, B and C establishes a TCP connection with ...
0
votes
1answer
197 views
Why is default gateway in routers configuration usually set as an IP address?
I mean why not just:
a MAC address? It should eliminate the need in ARP requests asking for gateway address. Also it should eliminate the need in changing IP addresses in settings when gateway IP is ...
4
votes
2answers
437 views
Is a datagram from an upper network layer converted 1:1 to one of the lower layer?
I know datagrams from upper layers are converted to those of lower layers by adding metadata, but I cannot seem to find this information anywhere. Which one of the below is correct?
A single TCP ...
0
votes
1answer
33 views
Unicast Adjacency Routes Nexus (AM) Cisco Nexus
I have an odd situation. There is static route on my Nexus 7700 that routes anything for specific subnet /24 to a F5 LTM Load Balancer, external VRRP interface 10.x.153.15.
As you can see below, ...
3
votes
1answer
65 views
What is the advantage of Supervised Machine Learning over Deep Packet Inspection in Network Traffic Classification?
As per the definition of Deep Packet Inspection (DPI), it uses signatures for packet filtering. Supervised Machine Learning can help put a label on a packet which does not get identified by Deep ...
4
votes
3answers
2k views
How does Deep Packet Inspection work with encrypted packets?
I've been reading up on Deep Packet Inspection for Software Defined Networks. However, I know that some applications use encryption to evade Deep Packet Inspection. Is there any alternative (such as ...
0
votes
1answer
60 views
What is the theoretical difference between the link layer and the network layer?
I have run into this problem again and again and have never found a sufficient answer to this question. I want to understand the fundamental, theoretical difference between a layer 2 network and a ...
0
votes
4answers
52 views
ACL on routers to block TCP/UDP ports
How routers understand the layer 4 port numbers to be blocked in ACL?
When an ACL to block TCP/UDP traffic with certain port numbers is applied on a router/L3 interface , how will router understand ...
0
votes
0answers
17 views
how OSI and TCP/IP layers work? [duplicate]
I am really confused by how the layers these model work. I'm not asking about what are their functions. I read that transport layer provides end-to-end of all packet delivery, and networking also ...
0
votes
3answers
84 views
Regarding Cisco's hierarchical network design
why routed ports usually implemented between the distribution layer and the core layer ? why not just extend the layer 2 domain to the core layer ? is the other design model more practical than this ...
0
votes
2answers
63 views
switch died after slow to rapid failure now DHCP will not function across network even with new switch
ok so i'm running out of ideas here.
we have/had 3 managed switches in our server rack and one in a closet; one hp procurve 3500yl 48 port with poe for 2 APs and 2 catalyst 2960s in the bottom of the ...
4
votes
3answers
361 views
Leaf-Spine network without routing
If I have a leaf-spine network with all the servers on the same subnet, say 10.10.0.0/16, do I need a router (or l3) since everything is on the same network and the network is flat?
1
vote
2answers
172 views
Why do transport layer do data chunking. If there is fragmentation in Network Layer
I just curiously wanted to know about the question regarding L4, L3 Data Chunks, IP Fragmentation :
Data chunking happened at Layer 4(Transport, TCP), and
Fragmentation at Layer 3(Network, ipv4)
...
0
votes
2answers
129 views
Different MAC addresses [closed]
What happens if a host on the network receives an IP packet with a MAC source address that differs from the MAC address in the local ARP table for that source IP.
The ARP table entry for that IP was ...
1
vote
2answers
137 views
Is a “LAN” a layer 2 or a layer 3 concept, in TCP/IP?
I think my question is purely theoretical and a matter of definitions; it derives from the fact that a L2-switch with VLAN capabilities is able to "create" different virtual LANs, and thus I am led to ...
0
votes
1answer
77 views
Layer 2 and Layer 3 traffic with one cable
Hers the topology.
L2 switch
L3 switch
Router
There are 2 VLANs. One VLAN ends on the L3 switch 1 VLAN on the router.
Here is the question. Can i connect the L3 switch and the router with just 1 ...
3
votes
2answers
244 views
What are neighboring ports?
I know this is as basic as it gets but I can't find a direct answer to this question.
Are they ports on two different switches (or routers) that are connected by a cable?
Are they the ports ...
2
votes
1answer
20 views
Understandable/Implementable explanation of CSMA p - persistent
I have been trying to understand how the CSMA P-persistent method works, but haven't been able to understand how it's implemented. I have referred to a few textbooks and other sources, but all of them ...
0
votes
1answer
281 views
Arp Cache Timeout [closed]
I'm trying to poll the arp table from a backbone switch but i want to understand which records are up. I just want to know if there is a specific time for the switch to keep a record on the arp table ...
3
votes
2answers
143 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 ...
3
votes
1answer
571 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)...
2
votes
1answer
696 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
votes
3answers
823 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
votes
3answers
822 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 ...
4
votes
2answers
202 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
321 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
78 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 ...
1
vote
1answer
99 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 ...
1
vote
2answers
33 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
vote
1answer
570 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
vote
1answer
243 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
942 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
314 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
821 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 ...
4
votes
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
vote
2answers
389 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
188 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
vote
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
99 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
vote
2answers
526 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 ...
1
vote
3answers
143 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 ...
1
vote
2answers
232 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 ...
4
votes
2answers
2k 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
vote
1answer
40 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
490 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
506 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 ...
