What does it mean saying the speed of a switch port (or router port)? In other word, does this mean that switch ports have a default-factory speed limit in some sense?
Thank you
Switch Port Speed – Meaning and Importance
ciscolayer1routerswitch
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So I've just tried this on an older 3750 (12.2(52)SE) and here's what I get - given the following configuration:
interface FastEthernet1/0/1
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1,5,500
switchport mode trunk
bandwidth 5000
spanning-tree link-type point-to-point
!
SNMP gives back the bandwidth value for the ifSpeed OID (bps):
IF-MIB::ifSpeed.10001 = Gauge32: 5000000
and a value of 5 for the ifHighSpeed (Mbps):
IF-MIB::ifHighSpeed.10001 = Gauge32: 5
Now, knowing that the ifIndex for fa1/0/1 is 10001 on this switch, I walked the entire MIB grepping for that index number, and there isn't a single relevant OID that gives a return value of 100000000 or 100.
So, long story short, it doesn't look like it is possible to return the physical link speed when the bandwidth parameter is set.
An HSRP group on an interface is an instance. Each layer-3 interface could have an HSRP group 1, but each is a different instance, and, indeed, are actually different HSRP groups, despite having the same number. The HSRP group is local to the interface, so HSRP group 1 on one interface is not the same HSRP group 1 on a different interface..
For example, you could have 32 interfaces, each with one HSRP group, 16 interfaces, each with two HSRP groups, one interface with 32 HSRP groups, or any combination, not to exceed 32 groups.
The "group" for HSRP is a group of routers (or layer-3 switches) on the same LAN that share an HSRP group number, not a group within the router. The router group will exchange HSRP messages on the LAN to determine which is the active router and which is the standby router for that group.
There are all types of documents that explain how HSRP works, and if you really understand how HSRP works, then you will understand that the groups on each interface are independent from the groups on any other interface. HSRP is configured on layer-3 interfaces, and each layer-3 interface in a router is in a different network, but HSRP must communicate with other HSRP routers on that network, and the standby address is only for that network. Remember that for your layer-3 switch, you can only create one SVI for each VLAN, and if you try to assign multiple interfaces in the same, or overlapping, network, you will get a configuration error.
RFC 2281, Cisco Hot Standby Router Protocol (HSRP) is one source of information, and it defines a standby group:
Standby Group - the set of routers participating in HSRP that jointly emulate a virtual router
As you can see, the group is the group of routers on a network, not a group of interfaces inside a router.
Best Answer
Switch ports normally can pass traffic at 10Mbps, 100Mbps or 1000Mbps. The default is for the switch port to auto-configure its speed based on signaling between the port and the connected device.
Sometimes auto-speed doesn't work that well and then, if possible, one could manually set the speed of a port (routers, too) with the "speed" or "set speed" command.
The vast majority of switches do not support speeds over 1000Mbps, there are very high-end (think major ISP or large datacenter equipment) switches that can to 10GbPS or 40GbPS now, too.