Go Premium for a chance to win a PS4. Enter to Win

x
?
Solved

Does Ping Packet go through Trunk port

Posted on 2016-10-19
4
Medium Priority
?
152 Views
Last Modified: 2016-10-29
If you have L2 Switch with different VLANs, then you Trunk the switch port  to a router trunk port.
Now if PC1 on Vlan 10 pings VLAN 20 (both are on the same switch), then the Ping packet will go through the trunk port of the switch to the Trunk port of the router then back the same path.

in this case can we say Ping works at Layer 2 or at both Layer 2 and Layer 3 ?


I also believe(correct me if I am wrong) The IP routing at the router level works without any extra configuration , not like at the L3 switch level where you have to add the command "IP Routing". correct ?



Thanks
0
Comment
Question by:jskfan
  • 2
  • 2
4 Comments
 
LVL 27

Expert Comment

by:skullnobrains
ID: 41849884
pings are IPs packets. IP is layer 3.

layer 3 packets don't "know" about your vlans. you can think of a vlan as a fake physical switch. IP packets will see it that way. they do not care about what actually happens on level 2

routing is activated by default in all routers as far as i know.
having IPs in each vlans will make the router natively route from one vlan to the next.
you don't need to create routes unless you have multiple routers in which case you need to tell to each router which of it's siblings has an ip in the destination lan
0
 

Author Comment

by:jskfan
ID: 41855635
But Ping Packet will still have to go from the PC plugged to L2 Switch then  through Uplink Port (The Trunk port) and come back to the PC
0
 
LVL 27

Accepted Solution

by:
skullnobrains earned 2000 total points
ID: 41855671
yes

- your host sees the destination is in a different network -> it looks the path up in the routing table
- it selects the router's ip
- it broadcasts an arp query demanding for the mac corresponding to the router's ip
- the router answers
- it sends the ping
- the switch tags it in VLAN10 and forwards it on the trunk port
- the router receives it tagged, and routes it tagged on vlan20 on the same port
- the packet is traverses the switch, and is sent untagged to the destination host
- pretty much the same happens the other way round for the pong
0
 

Author Closing Comment

by:jskfan
ID: 41865170
Thank you
0

Featured Post

How to Use the Help Bell

Need to boost the visibility of your question for solutions? Use the Experts Exchange Help Bell to confirm priority levels and contact subject-matter experts for question attention.  Check out this how-to article for more information.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

I eventually solved a perplexing problem setting up telnet for a new switch.  I installed a new Cisco WS-03560X-24P switch connected to an existing Cisco 4506 running a WS-X4013-10GE Sup II-Plus. After configuring vlans and trunking,  I could no…
Creating an OSPF network that automatically (dynamically) reroutes network traffic over other connections to prevent network downtime.
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…

876 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question