VLAN stacking is also called "802.1q tunneling" or "802.1q in 802.1q" or simply q-in-q. They all refer to the same thing.
The idea behind this technology is to allow service providers to provide transparent LAN services to customers. The VLAN ID is a 12-bit field, restricting you to 4096 VLAN IDs. IF a provider wanted to offer transparent ethernet services, the number of VLAN IDs it could use would quickly run out if it mapped a provider VLAN ID to every customer VLAN ID. The use of q-in-q means that you can use a single VLAN ID per customer, within which you could carry the full range of customer VLAN IDs. Theoretically, you could scale up to 4096*4096 VLAN IDs !! As an example, say a customer with VLANs 1, 2 , and 3 wants a transparent LAN service. The provider would allocate it a VLAN, say 100, within its core. Customer traffic would enter the provider network as tagged frames. The provider would then attached another tag on top of that, the one for VLAN 100. Therefore, the frames would have the following tags within the core: (100 1), (100 2) and (100 3). When switching within the core, the provider would only look at the top tag, 100. When a frame egresses the provider network, the provider strips the top tag, leaving the original VLAN tag in place.
Question We run asr9001 with XR 6.1.3, and we have a very long delay to
login w/ SSH 1 or 2 to the device compare to IOS device. After
investigation, the there is 1s delay between the client KEXDH_INIT and
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Introduction The purpose of this document is to demonstrate the Open
Shortest Path First (OSPF) behavior when the V-bit (Virtual-link bit) is
present in a non-backbone area. The V-bit is signaled in Type-1 LSA only
if the router is the endpoint of one or ...
Hi, I am seeing quite a few issues with patch install and wanted to
share my experience and workaround to this. Login to admin via CLI, then
access root with the “shell” command Issue “df –h” and you’ll probably
see the following directory full or nearly ...