From: netmod <[email protected]> on behalf of [email protected] <[email protected]> Sent: 20 October 2021 13:50
The confusion appears to stem from the exclusion of "chassis" in the first part of this sentence: "Any class of physical component, except a stack, may be contained within a chassis; a chassis may only be contained within a stack." <tp> Yes. I looked back and the text has been the same for decades so clearly the authors are happy with this. My initial take was on the common sense (to me) usage of chassis but this is a bit different. Perhaps raise an erratum which would likely get the attention of the authors and the AD with OLD and NEW as you suggest. Tom Petch It takes a rather pedantic read of the text to suggest that "any class of physical component" may also include a chassis, but perhaps it is worth updating the text to specifically state "Any class of physical component, except a stack or a chassis, may be contained within a chassis". Nesting a chassis within a chassis I don't see being useful to permit in practice/practically useful. Nested stacking sounds plausible. 'A stack of stacks' reminds me of a few designs I've seen in the past (4-way Cisco VSS, perhaps?) Regards, Tom My sincere apologies for Outlook. -----Original Message----- From: netmod <[email protected]> On Behalf Of tom petch Sent: 20 October 2021 12:10 To: Aihua Guo <[email protected]>; [email protected] Subject: Re: [netmod] Clarification on the description for chassis and stack in RFC 8348 From: netmod <[email protected]> on behalf of Aihua Guo <[email protected]> Sent: 13 October 2021 20:17 Hi All, RFC 8348 defines chassis and stack as two identities for networking equipment. The description for chassis says that "Any class of physical component, except a stack, may be contained within a chassis; a chassis may only be contained within a stack." First statement of this sentence seems to suggest that a chassis (which is a component) can also be contained within a chassis, while the next statement, "a chassis may only be contained within a stack." seems to suggest that a chassis can be only contained within a stack and not within another chassis, which seems to contradict with the previous statement. So, which statement is correct? <tp> I do not know what the authors had in mind but to me a chassis is clearly a chassis and a stack a stack:-) A chassis is a frame, usually metal, often with PSU and perhaps managements functions into which blades can be slotted. Without at least one blade it is usually not good for much except testing the management module although that may well be a blade and not integral with the chassis. A multi-protocol switch would be a likely example. I have not seen a chassis within a chassis. By contrast, a stack is made up of stackable elements, each of which is complete in itself and could be used by itself as a one element stack but which also have in/out sockets which enable multiple elements to be integrated into a single functional element. A LAN hub where each element supports 16 ports and eight can be stacked to form a 128 port hub would be an example. If the elements are all connected together, I see a stack. If they are physically co-located but function as several separate entities then I see several stacks but not a stack within a stack. HTH Tom Petch Another point to clarify is that in the description for stack, "...a stack may be contained within another stack. Only chassis components should be contained within a stack." Is it correct to understand that a stack can contain either another stack or a chassis, or both, but nothing else? I would appreciate the clarification. Thanks, Aihua _______________________________________________ netmod mailing list [email protected] https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.ietf.org%2Fmailman%2Flistinfo%2Fnetmod&data=04%7C01%7Ctom.2.hill%40bt.com%7Ceceaf59456654bcbc2cb08d993ba4469%7Ca7f356889c004d5eba4129f146377ab0%7C0%7C0%7C637703250499568112%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=hdfDrlNtUJpN%2FddyjlDwn5tjHDosdORIC0qa%2BmCA2fc%3D&reserved=0 _______________________________________________ netmod mailing list [email protected] https://www.ietf.org/mailman/listinfo/netmod _______________________________________________ netmod mailing list [email protected] https://www.ietf.org/mailman/listinfo/netmod
