Differences between 3550-24-SMI and 3550-24-EMI

Differences between 3550-24-SMI and 3550-24-EMI

Post by JohnNew » Sun, 19 Oct 2003 22:21:58



Folks:

Here are a few quick questions about the differences between 3550-24-SMI and
3550-24-EMI.  One vendor told me it is PERFECTLY OK to purchase 3550-24-SMI
(at a lower cost that EMI) and upgrade same to the 3550-24-EMI which can
then be used for CCNP/CCIE studies.  I am trying to determine if there are
any DOWNSIDES to this approach.

*   What are the main differences between 3550-24-SMI and 3550-24-EMI ?
*   Is it OK to purchase a Catalyst 3550-24-SMI at a lower cost and upgrade
to 3550-24-EMI for use in CCNP/CCIE Lab ?
*   Is it true that these two Catalyst Switches have identical hardware but
different IOS ?
*   If I upgrade the SMI to EMI do I then have a device identical (in
software & hardware) to an original Catalyst 3550-24-EMI ?

Thanks,
John

 
 
 

Differences between 3550-24-SMI and 3550-24-EMI

Post by Marcin Strzyzewsk » Sun, 19 Oct 2003 22:35:51



> Folks:

> Here are a few quick questions about the differences between 3550-24-SMI and
> 3550-24-EMI.  One vendor told me it is PERFECTLY OK to purchase 3550-24-SMI
> (at a lower cost that EMI) and upgrade same to the 3550-24-EMI which can
> then be used for CCNP/CCIE studies.  I am trying to determine if there are
> any DOWNSIDES to this approach.

> *   What are the main differences between 3550-24-SMI and 3550-24-EMI ?

The EMI enables a richer set of enterprise-class features, including
hardware-based IP Unicast routing (Open Shortest Path First [OSPF],
Interior Gateway Routing Protocol [IGRP], Enhanced IGRP [EIGRP], Border
Gateway Protocol Version 4 [BGPv4]), multicast routing, and policy-based
routing [PBR]).
Both the SMI and the EMI allow for Layer 3 and Layer 4 lookups for QoS
and security

The following features and functions are supported with the EMI:

     * Dynamic IP routing protocols for load balancing and constructing
scalable LANs:
     *
           o OSPF
           o IGRP and EIGRP
           o BGPv4
     * Equal-cost routing for load balancing and redundancy
     * Fallback bridging for forwarding of non-IP traffic between two or
more VLANs
     * Protocol Independent Multicast (PIM) for IP multicast routing
within a network that enables the network to receive the multicast feed
requested and for switches not participating in the multicast to be
prunedsupport for PIM sparse mode (PIM-SM), PIM dense mode (PIM-DM),
and PIM sparse-dense mode
     * Distance Vector Multicast Routing Protocol (DVMRP) tunneling for
interconnecting two multicast-enabled networks across nonmulticast networks
     * PBR, which allows superior control by enabling flow redirection
regardless of the routing protocol configured

Quote:> *   Is it OK to purchase a Catalyst 3550-24-SMI at a lower cost and upgrade
> to 3550-24-EMI for use in CCNP/CCIE Lab ?

its ok. for ccnp you dont need EMI image

Quote:> *   Is it true that these two Catalyst Switches have identical hardware but
> different IOS ?

yes

Quote:> *   If I upgrade the SMI to EMI do I then have a device identical (in
> software & hardware) to an original Catalyst 3550-24-EMI ?

yes

m.

 
 
 

Differences between 3550-24-SMI and 3550-24-EMI

Post by Steinar Ha » Sun, 19 Oct 2003 23:05:58


[Marcin Strzyzewski]

|   > *   What are the main differences between 3550-24-SMI and 3550-24-EMI ?
|  
|   The EMI enables a richer set of enterprise-class features, including
|   hardware-based IP Unicast routing

No, SMI does hardware based IP unicast routing just fine, including
static routes and (as far as I remember) RIPv2. Required a reasonably
new IOS version (to have this in SMI).


 
 
 

Differences between 3550-24-SMI and 3550-24-EMI

Post by One Step Beyon » Mon, 20 Oct 2003 02:08:42


Also, SMI cannot do dot1q on routed ports.  This is important if you wanted
to use a 3550 to route between VLANs on a trunk from, say, a rack of
switches.  There are means around this (like leave it as a switch port and
route on a SVI) but be aware of this limitation in SMI.
Remember that EMI AND SMI can only route IP.  They cannot route
IPX/Apple/DEC.

OSB


> [Marcin Strzyzewski]

> |   > *   What are the main differences between 3550-24-SMI and
3550-24-EMI ?
> |
> |   The EMI enables a richer set of enterprise-class features, including
> |   hardware-based IP Unicast routing

> No, SMI does hardware based IP unicast routing just fine, including
> static routes and (as far as I remember) RIPv2. Required a reasonably
> new IOS version (to have this in SMI).



 
 
 

Differences between 3550-24-SMI and 3550-24-EMI

Post by Steinar Ha » Mon, 20 Oct 2003 02:32:29


["One Step Beyond"]

|   Also, SMI cannot do dot1q on routed ports.  This is important if you wanted
|   to use a 3550 to route between VLANs on a trunk from, say, a rack of
|   switches.

Can the EMI version do this? Maybe you can post a configuration example.


 
 
 

Differences between 3550-24-SMI and 3550-24-EMI

Post by Jason Ka » Mon, 20 Oct 2003 05:15:10



> ["One Step Beyond"]

> |   Also, SMI cannot do dot1q on routed ports.  This is important if you wanted
> |   to use a 3550 to route between VLANs on a trunk from, say, a rack of
> |   switches.

> Can the EMI version do this? Maybe you can post a configuration example.

Why would you want to do dot1q on routed interfaces when you can do routing on
SVI interfaces?  That is, you setup your physical interface as a trunk port
and then you setup SVI interfaces (i.e. "interface vlan <number>") with the
layer 3 routing and route among the SVI interfaces.

--
Jason Kau
http://www.cnd.gatech.edu/~jkau

 
 
 

Differences between 3550-24-SMI and 3550-24-EMI

Post by Steinar Ha » Mon, 20 Oct 2003 05:43:33


[Jason Kau]

|  > |   Also, SMI cannot do dot1q on routed ports.  This is important if you wanted
|  > |   to use a 3550 to route between VLANs on a trunk from, say, a rack of
|  > |   switches.
|  >
|  > Can the EMI version do this? Maybe you can post a configuration example.
|  
|  Why would you want to do dot1q on routed interfaces when you can do routing on
|  SVI interfaces?  That is, you setup your physical interface as a trunk port
|  and then you setup SVI interfaces (i.e. "interface vlan <number>") with the
|  layer 3 routing and route among the SVI interfaces.

Sure, that is the "normal" way of doing it. If, however, you have VLAN
trunks with overlapping VLAN ranges, you cannot use SVIs. Subinterfaces
directly on the ports would be able to handle this, but I don't believe
the 3550 can do subinterfaces directly on the ports. 6500/7600 with
GE-WAN OSM can do it, and the good old 2948G-L3 can do it.


 
 
 

Differences between 3550-24-SMI and 3550-24-EMI

Post by One Step Beyon » Mon, 20 Oct 2003 21:15:40


3550 can do subinterfaces on the routed ports.  Even SMI can do this and
sure you can use secondary addresses on those subinterfaces with SMI.
However, you CANNOT do dot1q encapsulation on a routed port on the SMI
image.  You need to use the EMI image to do that.  As I said earlier, you'd
want to do this if you had a stack of purely layer 2 swicthes and wanted a
port to act as a trunk connected to one of the 3550 routed ports.  You
cannot do this by router on a stick with the SMI image since it does not
support dot1q on routed ports.

OSB


> [Jason Kau]

> |  > |   Also, SMI cannot do dot1q on routed ports.  This is important if
you wanted
> |  > |   to use a 3550 to route between VLANs on a trunk from, say, a rack
of
> |  > |   switches.
> |  >
> |  > Can the EMI version do this? Maybe you can post a configuration
example.
> |
> |  Why would you want to do dot1q on routed interfaces when you can do
routing on
> |  SVI interfaces?  That is, you setup your physical interface as a trunk
port
> |  and then you setup SVI interfaces (i.e. "interface vlan <number>") with
the
> |  layer 3 routing and route among the SVI interfaces.

> Sure, that is the "normal" way of doing it. If, however, you have VLAN
> trunks with overlapping VLAN ranges, you cannot use SVIs. Subinterfaces
> directly on the ports would be able to handle this, but I don't believe
> the 3550 can do subinterfaces directly on the ports. 6500/7600 with
> GE-WAN OSM can do it, and the good old 2948G-L3 can do it.



 
 
 

Differences between 3550-24-SMI and 3550-24-EMI

Post by Steinar Ha » Tue, 21 Oct 2003 02:35:59


["One Step Beyond"]

|   3550 can do subinterfaces on the routed ports.  Even SMI can do this and
|   sure you can use secondary addresses on those subinterfaces with SMI.
|   However, you CANNOT do dot1q encapsulation on a routed port on the SMI
|   image.  You need to use the EMI image to do that.

I'm willing to believe 3550-EMI and dot1q encapsulation on a routed port
if you can show me a working example - not otherwise. I can't find anything
in the documentation which indicates this is possible.


 
 
 

Differences between 3550-24-SMI and 3550-24-EMI

Post by Blaz Zupa » Tue, 21 Oct 2003 02:52:46



> 3550 can do subinterfaces on the routed ports.  Even SMI can do this and
> sure you can use secondary addresses on those subinterfaces with SMI.
> However, you CANNOT do dot1q encapsulation on a routed port on the SMI
> image.  You need to use the EMI image to do that.  As I said earlier, you'd
> want to do this if you had a stack of purely layer 2 swicthes and wanted a
> port to act as a trunk connected to one of the 3550 routed ports.  You
> cannot do this by router on a stick with the SMI image since it does not
> support dot1q on routed ports.

Not sure where you buy you 3550 EMI, but the ones I bought don't support dot1q
encapsulation on routed ports:

interface FastEthernet0/23
 no switchport
 no ip address
 shutdown
end

switch-mb4#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
switch-mb4(config)#int f0/23.1
switch-mb4(config-subif)#encapsulation dot1q 10
                          ^
% Invalid input detected at '^' marker.

switch-mb4(config-subif)#

It's running this IOS:

IOS (tm) C3550 Software (C3550-I5Q3L2-M), Version 12.1(13)EA1c,
RELEASE SOFTWARE (fc1)

 
 
 

Differences between 3550-24-SMI and 3550-24-EMI

Post by One Step Beyon » Tue, 21 Oct 2003 21:33:01


Take my word for it.


> ["One Step Beyond"]

> |   3550 can do subinterfaces on the routed ports.  Even SMI can do this
and
> |   sure you can use secondary addresses on those subinterfaces with SMI.
> |   However, you CANNOT do dot1q encapsulation on a routed port on the SMI
> |   image.  You need to use the EMI image to do that.

> I'm willing to believe 3550-EMI and dot1q encapsulation on a routed port
> if you can show me a working example - not otherwise. I can't find
anything
> in the documentation which indicates this is possible.



 
 
 

Differences between 3550-24-SMI and 3550-24-EMI

Post by Steinar Ha » Tue, 21 Oct 2003 23:59:03


["One Step Beyond"]

|   Take my word for it.
|  


|   > ["One Step Beyond"]
|   >
|   > |   3550 can do subinterfaces on the routed ports.  Even SMI can do this
|   and
|   > |   sure you can use secondary addresses on those subinterfaces with SMI.
|   > |   However, you CANNOT do dot1q encapsulation on a routed port on the SMI
|   > |   image.  You need to use the EMI image to do that.
|   >
|   > I'm willing to believe 3550-EMI and dot1q encapsulation on a routed port
|   > if you can show me a working example - not otherwise. I can't find
|   anything
|   > in the documentation which indicates this is possible.

I'm afraid your word is absolutely useless here - it doesn't help me
find out *how* to do this if it were indeed possible. So until this is
documented, or somebody shows a working example, I'm going to assume
it is *not* possible.


 
 
 

1. Cisco Catalyst 3550-24 SMI to EMI conversion

Hi, I'm planning to buy a 3550 for my CCIE study lab & need to know if
ANY Cisco Catalyst 3550-24 SMI can be converted to EMI by changing the
IOS image or has Cisco created some restrictions whereby these can only
be upgraded on certain models and not on certain ones.

I know of people who have upgraded their 3550 SMI switches to EMI
images, but have recently heard that Cisco was planning to change
something whereby this is no longer possible.

Also, please also advise me on Catalyst 3750 switches. Are these going
to be replacing the 3550s in the lab & will 3550s remain suitable
enough for lab practice or will there be features that are not
available in the 3550s but present in the 3750s that will make
investment in 3550s not very advisable?

Request a clarification.

Thanks!
SB

2. USB and Storage...ORB in particular

3. cisco 3550 24 port SMI

4. DOS/16M [6] out of memory error

5. Catalyst 3550 SMI / EMI differences?

6. All===Writers!!!!....

7. Cisco Catalyst 3550-12T and 2950T-24

8. Cisco 3550-24 and Cisco 2950 - poor performance.

9. Catalyst 3550-24 and full BGP

10. UPGRADING 3550 SMI to EMI

11. 3550 emi vs smi

12. 3550 -- SMI vs. EMI