HP 1920 connecting to HP 1800 and Dell N2048 (Tunk Question)

[Kevin-Merritt]

I hope someone can help,
We have 5 x HP 1820 switches connected via Trunk on each using the SFPs, Recenetly we put a HP 1920 in front of a 1820 due to needing more connectivity, However this 1920 will not connect to our Dell N2048 using dual SFP on a trunk, as soon as its connected (Both SFPs) the network storms and crashes.
I Do have the 1820 sat behind the 1920 using Trunks on Ports 51 and 52 and that does allow communications.
I need ports 49, 50 to be a Tunk to our Dell with VLANs 1, 10, 20, 30 which is currently setup for ports 49 - 52.

Can Anyone help?

[parnassus]

With the word "Trunk" are you referring to "Aggregated Links"?

Network topology (schema please)?

The rule is: a Port Trunk = Aggregated Link means that you have 2 or more ports (up to 8, generally) that are aggregated into a logical port (the Trunk)...this port should be used as the only item you play with when setting VLAN tagging/untagging (to define which VLAN IDs are permitted over the  logical port).

If you connect two physical interfaces of the same Switch to two physical interfaces of a peer Switch AND no Port Trunk is defined on both ends THEN you are creating a loop (-> Broadcast Storm -> Network Crash IF Spanning-Tree is not correctly configured on both switches).

SO you need to be sure how your network is currently configured to be sure that adding a new switch will not cause you unwanted issues (as it is currently happening). 

[Kevin-Merritt]

Each of our Switches have 2 SFP connections back to a Dell N4032F. So each Switch is setup as they are only L2 Switches as TUNK ports on 25/26 or 49/50 as TRUNK 1 back to a Dedicated Trunk within the Dell Switch. These have worked and are working at present, the issue we have is putting the 1920 in front is a L3 Switch and it doesn't work the same as the L2....
I could upload pictures showing the connections and the configs, the L2 show as SMAC or DMAC, there is no LACP setup on any other switches that are working..