05-28-2024 04:29 AM
Hi,
My Cisco 2960-X switches have multiple versions of STP.
I would like to know what the differences are between these, and which ones are compatible with the generic industry standard STP and then the quick version of STP.
My network still has a few switches which are not Cisco, and hence, I believe I must use the industry standard version if I want this to work across my entire network properly.
Below is a screenshot of the options I can choose.
05-28-2024 04:37 AM
An explanation as to what these options are would also be very appreciated.
Most of my ports say they are configured with 'spanning-tree portfast'
05-28-2024 07:16 AM
Hello @tmourelle
The Cisco 2960-X switches offer several versions of Spanning Tree Protoco: MST (Multiple Spanning Tree), PVST (Per-VLAN Spanning Tree), and Rapid-PVST (Rapid Per-VLAN Spanning Tree).
MST allows multiple VLANs to be mapped to a single spanning tree instance, reducing the number of instances required and hence conserving switch resources, making it suitable for larger, more complex networks. PVST, on the other hand, maintains a separate spanning tree instance for each VLAN, which can provide optimized traffic paths but at the cost of increased resource consumption. Rapid-PVST is an enhancement of PVST that incorporates features of the IEEE 802.1w standard, offering faster convergence times than traditional STP. In terms of compatibility with industry standards, the IEEE 802.1D standard refers to the traditional STP, which ensures a loop-free network topology but converges relatively slowly. For faster convergence, the IEEE 802.1w standard defines the Rapid Spanning Tree Protocol, which is essentially what Rapid-PVST implements on a per-VLAN basis. If your network includes non-Cisco switches, you will need to ensure compatibility by using the industry-standard versions: IEEE 802.1D (STP) or IEEE 802.1w (RSTP). MST, as defined by the IEEE 802.1s standard, also offers industry-standard compatibility while providing scalability and efficiency for larger networks.
The 'spanning-tree portfast' command configures a port to immediately transition to the forwarding state, bypassing the listening and learning states that are part of the traditional STP process. This is typically used for ports connected to end devices (like PCs or servers) to speed up their connection time. PortFast should not be enabled on ports connected to other switches to avoid potential network loops.
Given your mixed network environment with non-Cisco switches, it is crucial to ensure compatibility across all devices:
-- MST: If your network includes switches from multiple vendors, MST is likely the best choice due to its industry-standard status and ability to scale efficiently.
-- Rapid PVST+: If you have mostly Cisco switches and need rapid convergence, Rapid PVST+ offers enhanced performance but ensure that non-Cisco devices can support RSTP for compatibility.
If your network is predominantly Cisco, you can benefit from the advanced features and faster convergence of Rapid PVST+. For a mixed-vendor environment, MST provides a balance of compatibility and efficiency, making it suitable for larger, more complex networks with diverse hardware.
05-28-2024 07:28 AM
Thankyou for the detail, this is a massive help.
Some of my switch have 'spanning-tree edge' instead of 'portfast'
What is the difference?
05-28-2024 01:31 PM
You're so welcome @tmourelle
Both configurations achieve the same primary goal: making the port immediately transition to the forwarding state, skipping the usual STP progression through listening and learning states.
05-29-2024 03:28 AM
Hello @tmourelle ,
spanning-tree portfast is a Cisco term that applies also to PVST.
spanning-tree edge is the term used in Rapid STP standard 802.1w.
in both cases ports to user devices configured with this will skip the learning and listening states in traditional STP and they will not trigger a Topology Change notification to be sent upstream to the root bridge.
Spanning-tree edge is very important in Rapid STP because without defining the edge ports Rapid STP convergence is not fast.
On standard STP ports with other switches Rapisd STP attempts to use hanshake of STP BPDUs. This is not necessary on post towards end users.
Hope to help
Giuseppe
05-29-2024 03:45 AM
So to confirm, I must have either portfast or edge on all ports I want STP to work on.
Edge is used for the RSTP
Portfast is used for STP
Depending on the version of STP I use, I must choose the correct protocol; edge or portfast if I want the right functionality?
Because I have different vendor switches in my network (soon to be replaced but until then) I must disable portfast and/or edge on any ports that connect to switches. Edge and portfast are only to be enabled on ports connected to end devices.
Does this also apply to routers and other devices that use the STP protocol?
I have Unifi SAT-Lite Beams and Mikrotik routers that also use the STP protocol you see... They will not be getting replaced as they are essential to my network - so I assume I can only ever use the industry standard STP and never enable edge or portfast on the ports that connect to these devices?
05-29-2024 03:49 AM
spanning-tree edge <<- this command appear under the interface ??
MHM
05-29-2024 03:52 AM
Yes, that is on some of my interfaces.
Some say portfast.
Trying to understand the difference. I believe I understand now, just need a response to my above reply to confirm I have understood.
05-29-2024 04:12 AM
Can I see screenshot
MHM
05-29-2024 06:08 AM
05-31-2024 12:29 AM
that clear
there is no command
spanning tree edge
there is command
spanning tree portfast edge
and both same it put the Port in FWD status immediately without waiting learn and listen phase complete.
MHM
06-05-2024 02:00 AM
I'm sorry but I'm struggling to understand you here.
Can you please re-phrase the post as it doesn't make sense...
06-07-2024 01:12 AM
spanning tree edge <<- this not correct
spanning tree portfast edge <<- this correct
spanning tree portfast <<- this correct and same as spanning tree portfast edge
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