Cisco Cisco Nexus 5010 Switch Guía De Diseño
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In Cisco NX-OS 5.1, a fixed range of 80 VLANs is reserved in the VLAN range 3968 to 4047. In Cisco NX-OS 5.2
(which is not available on the Cisco Nexus 5000 Series at the time of this writing), the range of reserved VLANs is
Cisco NX-OS 5.2 allows the range of VLANs to be shifted using the following command:
[no] system vlan <start-vlan> reserve
Cisco Nexus 5020 and 5010
Starting from Cisco NX-OS Release 4.1(3)N1, the Cisco Nexus 5000 Series hardware supports 507 concurrent
VLANs (see the discussion of VLANs later in this chapter for details). You can use any VLAN in the ranges 1
through 3967 and 4048 through 4093 as long as the total number of concurrent VLANs does not exceed the
maximum. Note that some VLANs may also be used as VSANs, in which case they are not available for regular
LAN traffic (see the section “VLAN Allocation on Cisco Nexus 5000 Series” earlier in this chapter for details).
LAN traffic (see the section “VLAN Allocation on Cisco Nexus 5000 Series” earlier in this chapter for details).
The Cisco Nexus 5000 Series hardware supports a total of 512 VLANs, with the following stipulations:
●
Of the total number of VLANs supported, 507 VLANs are available for use, and 5 VLANs are used
internally.
●
If you enable FCoE by using the command feature FCoE, two internal VSANs are allocated, which brings
the total of available VLANs to 505.
●
When you configure FCoE, each VSAN or VLAN requires two resources: one VLAN for FCoE and the
VLAN hardware resource for Fibre Channel. Thus, the total number of available VLANs for TCP/IP traffic
with FCoE deployments is 505 minus 2 times the number of VSANs.
You can use the command show resource vlan to verify VLAN use.
For example, if you have 32 VSANs, and if the software uses 7 VLANs internally to manage fabric extenders and
for internal VSAN purposes, you can use 512 - 32 - 7 = 473 VLANs. In the following example, the user has
configured 14 VLANs, so 459 VLANs are still available:
tc-nexus5k01# show vsan usage
32 vsan configured
tc-nexus5k01# show vlan summary
Number of existing VLANs : 14
Number of existing user VLANs : 14
tc-nexus5k01# show resource vlan
Resource Min Max Used Unused Avail
----------- ----- ----- ------ -------- -------
vlan 16 512 53 0 459
Spanning-Tree Best Practices
The fundamental concept to remember when operating a Cisco Nexus 5000 Series Switch in vPC mode is that
from a spanning-tree perspective, Cisco Nexus 5000 Series vPC pairs appear to operate as a single device on
vPC ports:
●
Only the vPC primary link processes Bridge Protocol data units (BPDUs).
●
The peer link is never blocking.