From: Stan Buskus (stan.buskus@xxxxxxx)
Date: Sun Aug 13 2000 - 17:23:48 GMT-3
Ironically several techs and myself had a discussion about where does the
4908G-L3 fit in the Cisco product line. The most apparent advantage we found
was that the 4908 has twice the back plane speed over the 3500, but in our
opinion the 10G back plane on the 3500 should handle the aggregate bandwidth
from most closets. In your example, the 4908 is way over kill.
Also the price difference between the 4908 and the 3500 is considerable with
the 4908 considerably higher. Given the economic realities, I think some
customers would choose the 3500.
The other disadvantage for the 4908 is the scalability for configuring
trunking. In your example, the 4908 is very easy and straight forward to
configure, but if the user requires that VLAN2 should be in all closets, than
configuring the 4908 starts to become more complicated. Also, if the users
wants to add more vlans you need to configure the additional interfaces for
each vlan on each trunk. Whereas, on a 3500 once you have configured trunking
you normally do not need modify the trunks for additional vlans.
Stan Buskus
Philip Lai wrote:
> Network Design issue.
>
> 6500(L3)- 6500 (L3) Core
> / \
> 4908G(L3) 4908G(L3) Distribution
> / \ / \
> 2924M 2924M 2924M 2924M Access
> A B C D
> Vlan1 Vlan2 Vlan3 Vlan4
>
> Server Farm will be directly attached to the Core. There will be some
> departmental servers in zone A for both zone A and B users.
>
> My friend has designed a switching network like this and claim that it will
> have better performance than using 3508G (L2) in the distribution layer.
> Since the 4908G has the L3 routing feature, when zone A transfer packet to
> zone B, that traffic will pass only the 4908G but not the 6500 (Core). Thus,
> the bandwidth from the 6500 to 4908G can be saved.
>
> My questions:
> 1. If both the Core and Distribution switch are routing enabled, that
> switches has to be the VTP server. ie: 4 indentical Vlan database are keep
> by each switches (Core & Dist.)
> 2. Does it meaningful to configure trunk mode between all switches in order
> to pass the Vlan information ? If all 2924M are in VTP clients mode, which
> switches should be the VTP server ? and why?
> 3. A crazy idea is to think about the L3 switches as a individual router.
> Then apply OSPF between to each one and enable routing. Will the network be
> quite slow for this design, compared with the standard design.-- Core
> (Routing)--Dis(Switching)---Access(Switching) ?
>
> 4. In fact, I recommend the stand design using 3508G for dist. But could you
> tell me the adv and Disadv for using this and the design above ?
>
> Thank you very much for every reply
>
> Philip Lai
>
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