Solved

"portfast" can connect with switch or not

Posted on 2014-11-25
8
302 Views
Last Modified: 2014-11-27
hello Experts
below is the extract from Cisco web site, i am a little puzzled, the "portfast" port could or could not connected with a switch?

thank you

PortFast causes a switch or trunk port to enter the spanning tree forwarding state immediately, bypassing the listening and learning states.

You can use PortFast on switch or trunk ports that are connected to a single workstation, switch, or server to allow those devices to connect to the network immediately, instead of waiting for the port to transition from the listening and learning states to the forwarding state.


Caution  You can use PortFast to connect a single end station or a switch port to a switch port. If you enable PortFast on a port that is connected to another Layer 2 device, such as a switch, you might create network loops.
0
Comment
Question by:beardog1113
8 Comments
 
LVL 6

Accepted Solution

by:
Matt earned 200 total points
ID: 40463959
You should use "spanning-tree portfast" option only on ports with end-points connected (workstations, servers, printers). On ports where you have additional network device (hub,switch) do NOT use portfast.
0
 

Author Comment

by:beardog1113
ID: 40463963
You can use PortFast on switch or trunk ports that are connected to a single workstation, switch, or server to allow those devices to connect to the network immediately

hello
for this sentence does it mean trunk mode port can be connect with switch?
or it is different meaning of this sentence?
or "switch" not meaning switch?

thank you
0
 
LVL 6

Assisted Solution

by:Matt
Matt earned 200 total points
ID: 40463973
To prevent loops from occuring in a network, the spanning tree PortFast mode should be configured only on nontrunking access ports because these ports typically do not transmit or receive BPDUs. The most secure implementation of PortFast is to enable it only on ports that connect end stations to switches.
0
 
LVL 17

Assisted Solution

by:lruiz52
lruiz52 earned 100 total points
ID: 40464016
In agreement with Matt, switch means switch L2 device. Sentence gates you can enable portfast on an interface connected to another switch but you run the risk of creating a network loop.
0
Scale it in WD Gold

With up to ten times the workload capacity of desktop drives, WD Gold hard drives employ advanced technology to deliver among the best in reliability, capacity, power efficiency and performance.

 

Author Comment

by:beardog1113
ID: 40464031
hello
if i have bpdu guard enabled, may i connect "portfast" port with a switch?

thank you
0
 
LVL 27

Assisted Solution

by:Predrag Jovic
Predrag Jovic earned 100 total points
ID: 40464248
if i have bpdu guard enabled, may i connect "portfast" port with a switch?
You can and it is safe to implement portfast that way.

Also, you can set porfast if you connect some third party unmanaged switch that has connected host devices, since those small switches don't send BPDU (STP is not present usually on those switches). BPDU guard with portfast is recommended also in that case, since if you create a loop in network with unmanaged switch switch will receive its own BPDU (or any other BPDU) and port will enter error-disabled state.

So, sure you can do that, but ... is it safe and for what purpose is better question?
0
 
LVL 50

Assisted Solution

by:Don Johnston
Don Johnston earned 100 total points
ID: 40464423
"can" means is possible.   As in: It is possible to configure portfast on an interface which will be connected to another switch.  Because it's possible doesn't make it a good idea.

Conversely, you can not connect an RJ-45 plug into an SFP socket.
0
 

Author Closing Comment

by:beardog1113
ID: 40468528
thank you all
0

Featured Post

Control application downtime with dependency maps

Visualize the interdependencies between application components better with Applications Manager's automated application discovery and dependency mapping feature. Resolve performance issues faster by quickly isolating problematic components.

Question has a verified solution.

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

Suggested Solutions

Title # Comments Views Activity
Is this network design suitable? 3 63
HSRP not working on N7K-c7018 3 42
slow vpn connection 9 40
Need help with VLAN issue 6 35
Security is one of the biggest concerns when moving and migrating your data from your on-premise location to the Public Cloud.  Where is your data? Who can access it? Will it be safe from accidental deletion?  All of these questions and more are imp…
Microservice architecture adoption brings many advantages, but can add intricacy. Selecting the right orchestration tool is most important for business specific needs.
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…

911 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

Need Help in Real-Time?

Connect with top rated Experts

21 Experts available now in Live!

Get 1:1 Help Now