Ios on

How to Reload Your Cisco Router While Asleep

Sat, 14 Sep 2013 21:31:13 +0200

There are times when you want to schedule a router reload, but you don’t want to stay late or come to the office during weekends. “Reload at” is your friend.

How to reload your router at a predefined time

You want to reload your router (or switch) at 7pm, but at the same time, you’ll be having a coffee with your friend and you don’t want to have this discussion: “- Sorry guys, I have a router to reboot. I’ll be back in 30mn.

Cisco Switching Notes

Thu, 09 Feb 2012 21:31:13 +0200

a 3750 can act as a layer3 switch by adding the “ip routing” command.
It can automatically route between locally created vlans because it considers them as connected interfaces (given that the SVIs are created).
on a device, there are 3 types of traffic: control, management, end user.
Control traffic such as CDP, DTP, PAgP goes through vlan1 between Cisco switches, even if you clear it from trunks.
By default, native vlan traffic is untagged. But there’s a Cisco command that tells the switch to tag all vlans.
by default, native vlan = vlan1. If we set the native vlan to vlan100, then vlan100 frames will be untagged on trunks, and vlan1 frames will be tagged.
SMI: Standard Multilayer Image
EMI: Enhanced Multilayer Image
if switch is acting L2, then we should set a Default Gateway on it to make the management vlan reachable remote ; if it is acting L3, it will have routes instead.
switch and Management vlan
the management IP address must be reachable from remote
best practice: use a same subnet to manage all network devices
on L2 SW: only one SVI is up at a time

Cisco Auto Qos Configuration

Mon, 08 Aug 2011 21:31:13 +0200

First, let’s see if QoS is enabled on the switch: QoS is disabled. We should enable it on global configuration level: If we want to display QoS settings for an interface, we do a show mls qos interface command: At this stage we still did not define trust boundaries. That’s why Trust State and Trust Mode say “not trusted”. And we did not specify whether we’ll trust a device or not. To define trust boundary with auto-qos, we either trust all CoS values coming on the switch interface or we trust CoS values only if an ip phone is connected to the switch port. With auto qos voip trust, we tell the switch to trust CoS on each packet coming on the switch interface: If we want to further limit trust boundary, we can tell the switch to trust CoS values only if a Cisco ip phone is detected on the port: Finally, on a 3550 switch, show auto qos and show auto qos interface give the same output: