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Features

Masquerading impact on performance

While IP masquerading is useful in some situations, there is a cost in terms of resources associated with its use. The amount of extra CPU usage will depend on the number of concurrent sessions being masqueraded. As the number of concurrent sessions approaches the amount of permissible ports on the masqueraded IP pool, the CPU usage will be significantly affected as each lookup in the masquerading hash table will likely result in a collision. You can monitor the usage ratio on an IP pool with masquerading with the “sh poolip” command:

Ex: Masquerading[usage tcp 1/64468 0.002 %, udp 0/64468 0.000 %, icmp 0/65536 0.000 %]

Please keep in mind that if you plan to use masquerading with a large source network (a /18 for example) you will likely see higher CPU usage. The masquerading operation for this many source IPs into a single IP address is typically CPU intensive.

Avoid masquerading where it is not needed and prefer the use of 1-to-1 NAT whenever possible.

 

Does the Link LB support 802.1q trunking?

Yes it does, you can have a 802.1q trunk connected directly to the inside or outside ports of the Link LB. To use a vlan as a subinterface in the VFI configuration use the ethX.YYY notation where 'X' refers to the number of the port where you physically connected the network cable and 'YYY' refers to the vlan number you want to attach.

 

What are dynamic interfaces?

With the newly released 3.4.3 EOS version, we have changed the way to configure VLANs. The new dynamic interfaces will be the foundation and enable the use of new types of links in the future such as: bonded ethernet links (802.3ad) and cellular links over usb. 
 
After doing the EOS update and booting the unit for the first time, the previous configuration method will automatically adapt and create the required lines.
 
When using VLANs in a VFI, you need to "attach" the relevant interface and VLAN on the VFI. This part of the configuration has not changed.  
 
When adding new VLANs to your configuration, the following commands will now be required before attempting to run the "attach" command. In effect, the new commands "create" the VLAN interfaces explicitly where before the VLANs were created dynamically.
  
Example: 
 
Before:
 
---VFI CONFIG---
 
##
vfi0
## EOS Version [3.3.0]
## ( vfi0 )
  clr all
## Description
  description OLD Config Example
## Inside interface
  attach in eth3
## Outside interface(s)
  attach out eth1.50,eth1.60
 
----------
 
After:
 
---SYSTEM CONFIG---
 
##
syst
## EOS Version [3.4.3]
## Dynamic network interfaces
  dyn int 1 trunk_vlan_50 dot1q 50 eth1
  dyn int 2 trunk_vlan_60 dot1q 60 eth1
##[…]
 
---VFI CONFIG---
 
##
vfi0
## EOS Version [3.4.3]
## ( vfi0 )
  clr all
## Description
  description NEW Config Example
## Inside interface
  attach in eth3
## Outside interface(s)
  attach out eth1.50,eth1.60
##[…]