Trunks between switches normally use 802.1q or ISL encapsulation. ISL is Cisco propritary where as do1q is IEEE standard. VTP, the protocol that is propagated across trunk links to maintain VLAN consistency is layer 2 (if that is what you are asking)
802.1Q trunks are encapsulated within the ethernet frame at layer 2 using an internal tag this is to allow multivendor support. ISL on the other hand is still at layer 2 but has an external tag which in contrast extends the size of the ethernet frame and makes the method Cisco proprietary. All tagging terminates at router boundaries and does not extend into layer 3.
We are pleased to announce availability of Beta software for 16.6.3.
16.6.3 will be the second rebuild on the 16.6 release train targeted
towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are
looking for early feedback from customers befor...
Introduction Featured Speakers Luis Espejel is the Telecommunications
Manager of IENova, an Oil & Gas company. Currently he works with Cisco
IOS® and Cisco IOS XE platforms, and NX to some extent. He has also
worked as a Senior Engineer with the Routing P...
In this session you can learn more about Layer 3 multicast and the best
practices to identify possible threats and take security measures. It
provides an overview of basic multicast, the best security practices for
use of this technology, and recommendati...