{"id":587,"date":"2012-12-14T14:35:24","date_gmt":"2012-12-14T13:35:24","guid":{"rendered":"http:\/\/blog.robinward.com\/?p=587"},"modified":"2013-08-15T15:18:03","modified_gmt":"2013-08-15T14:18:03","slug":"lab-layer-3-switching-pt-3-inter-vlan-routing-with-switched-virtual-interfacessvi","status":"publish","type":"post","link":"https:\/\/robinward.com\/?p=587","title":{"rendered":"Lab: Layer 3 Switching Pt.3 \u2013 Inter VLAN Routing with Switched Virtual Interfaces(SVI)"},"content":{"rendered":"

With Switched Virtual Interfaces, a Layer 3 Switch can forward packets between networks on its own – no external Router required.<\/p>\n

Compared to a normal Router with FastEthernet or GigabitEthernet Interfaces, Layer 3 Switches using SVI can forward packets between VLANS at backplane speed! To get an idea how SVI works, take a look at this graphic:<\/p>\n

 <\/p>\n

 <\/p>\n

\"\"<\/a><\/p>\n

In this example we have 3 VLAN on the Layer 3 Switch: Vlan 20, 30 and 40. To be able to forward packets, IP Routing first needs to be enabled on a Layer 3 Switch:<\/p>\n

sw1(config)#ip routing<\/code><\/p>\n

As we need a gateway for each VLAN, we simply assign the gateway IP address to the equivalent VLAN Interface. Note that I left out the subnet mask in the image due to space restrictions. After that we put the VLAN interface online using the no shut<\/code> command. You should see IP Addresses assigned to your VLAN Interfaces when using the sh ip int brief<\/code> command.<\/p>\n

Once your VLAN Interfaces are up and running with an assigned IP Adress, your switch is ready to forward packets.<\/p>\n

Note: SVIs are also used to provide Layer 3 connectivity to a switch – for example if you want to access the switch via SSH or Telnet<\/del><\/span> (seriously, do no use Telnet if you can use SSH).<\/p>\n

The advantages of using SVIs to forward packets between your VLANs compared to using a Router or Router on a Stick are pretty obvious: Speed and Port density.<\/p>\n

The disadvantage of this method is pretty obvious as well: It requires a Layer Switch such as the 3750 im using in my lab.<\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

With Switched Virtual Interfaces, a Layer 3 Switch can forward packets between networks on its own – no external Router required. Compared to a normal Router with FastEthernet or GigabitEthernet Interfaces, Layer 3 Switches using SVI can forward packets between VLANS at backplane speed! To get an idea how SVI works, take a look at … <\/p>\n

Continue reading “Lab: Layer 3 Switching Pt.3 \u2013 Inter VLAN Routing with Switched Virtual Interfaces(SVI)”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[34,3],"tags":[],"class_list":["post-587","post","type-post","status-publish","format-standard","hentry","category-cisco","category-net"],"_links":{"self":[{"href":"https:\/\/robinward.com\/index.php?rest_route=\/wp\/v2\/posts\/587","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/robinward.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/robinward.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/robinward.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/robinward.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=587"}],"version-history":[{"count":4,"href":"https:\/\/robinward.com\/index.php?rest_route=\/wp\/v2\/posts\/587\/revisions"}],"predecessor-version":[{"id":592,"href":"https:\/\/robinward.com\/index.php?rest_route=\/wp\/v2\/posts\/587\/revisions\/592"}],"wp:attachment":[{"href":"https:\/\/robinward.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=587"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/robinward.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=587"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/robinward.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=587"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}