Would you like to inspect the original subtitles? These are the user uploaded subtitles that are being translated: 1 00:00:00,000 --> 00:00:05,000 align:middle line:84% Many Cisco switches support Dynamic Trunking Protocol or DTP 2 00:00:05,000 --> 00:00:11,000 align:middle line:84% this allows switches to dynamically negotiate the forming of trunks 3 00:00:11,000 --> 00:00:14,000 align:middle line:84% DTP is a Cisco propriety protocol 4 00:00:14,000 --> 00:00:17,000 align:middle line:84% and hence other vendors don’t support it 5 00:00:17,000 --> 00:00:20,000 align:middle line:84% a lot of switches have this configured by default 6 00:00:20,000 --> 00:00:23,000 align:middle line:84% which means that they can automatically negotiate 7 00:00:23,000 --> 00:00:26,000 align:middle line:84% trunking with neighboring switches. 8 00:00:26,000 --> 00:00:32,000 align:middle line:84% It’s, however, best practice to disable DTP and use manual configuration 9 00:00:32,000 --> 00:00:39,000 align:middle line:84% 2 Cisco switches can dynamically through DTP negotiate to form a trunk 10 00:00:39,000 --> 00:00:42,000 align:middle line:84% and permit VLANs across the trunk automatically 11 00:00:42,000 --> 00:00:48,000 align:middle line:84% it can also negotiate the protocol used such as the ISL or 802.1Q 12 00:00:48,000 --> 00:00:50,000 align:middle line:84% I’ll show you demonstration of DTP in a moment 13 00:00:50,000 --> 00:00:56,000 align:middle line:84% but DTP supports 2 main modes, dynamic auto and dynamic desirable. 14 00:00:56,000 --> 00:01:02,000 align:middle line:84% Desirable means that the switch initiates trunking with the remote end. 15 00:01:02,000 --> 00:01:05,000 align:middle line:84% Auto means that it doesn’t initiate 16 00:01:05,000 --> 00:01:10,000 align:middle line:84% but if the other side initiates the trunking, trunking will be formed. 17 00:01:10,000 --> 00:01:15,000 align:middle line:84% So as an example if you have 2 switches configured for dynamic desirable 18 00:01:15,000 --> 00:01:18,000 align:middle line:84% a trunk will be formed between the 2 switches. 19 00:01:18,000 --> 00:01:21,000 align:middle line:84% If 1 side is set up with dynamic desirable 20 00:01:21,000 --> 00:01:24,000 align:middle line:84% and the other side is using dynamic auto 21 00:01:24,000 --> 00:01:27,000 align:middle line:84% trunking will be formed but if both sides 22 00:01:27,000 --> 00:01:33,000 align:middle line:84% using dynamic auto neither side initiates the trunking. 23 00:01:33,000 --> 00:01:35,000 align:middle line:84% So the port becomes an access port. 24 00:01:35,000 --> 00:01:40,000 align:middle line:84% It is better practice, however, to configure both sides manually 25 00:01:40,000 --> 00:01:43,000 align:middle line:84% for trunking or configure both sides as access ports. 26 00:01:43,000 --> 00:01:50,000 align:middle line:84% DTP packets are sent using CLAN 1 when ISL is used. 27 00:01:50,000 --> 00:01:55,000 align:middle line:84% When 8021.Q trunking is used, DTP packets are sent on the native VLAN 28 00:01:55,000 --> 00:02:00,000 align:middle line:84% this is the case even if the native VLAN is cleared from the trunk 29 00:02:00,000 --> 00:02:05,000 align:middle line:84% on ISL trunks, DTP packet are sent on VLAN 1 30 00:02:05,000 --> 00:02:10,000 align:middle line:84% even if VLAN 1 is cleared from the trunk. 3542