DELL S50V User Manual

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sFlow
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Important Points to Remember
The IP destination address has to be learned via BGP in order to export extended-gateway data, prior to 
FTOS version 7.8.1.0.
If the IP destination address is not learned via BGP the Dell Force10 system does not export 
extended-gateway data, prior to FTOS version 7.8.1.0.
FTOS 7.8.1.0 and later enhances the sFlow implementation for real time traffic analysis on the 
E-Series to provide extended gateway information in cases where the destination IP addresses are 
learned by different routing protocols, and for cases where the destination is reachable over ECMP.
If the IP source address is learned via IGP then srcAS and srcPeerAS are zero.
The srcAS and srcPeerAS might be zero even though the IP source address is learned via BGP. The 
Dell Force10 system packs the srcAS and srcPeerAS information only if the route is learned via BGP 
and it is reachable via the ingress interface of the packet.
The previous points are summarized in following table.
Table 47-1.  Extended Gateway Summary
IP SA
IP DA
srcAS and 
srcPeerAS
dstAS and 
dstPeerAS
Description
static/connected/IGP
static/connected/IGP
Extended gateway data is not 
exported because there is no AS 
information.
static/connected/IGP
BGP
0
Exported
src_as & src_peer_as are zero 
because there is no AS information 
for IGP.
BGP
static/connected/IGP
Exported 
Exported 
Prior to FTOS version 7.8.1.0, 
extended gateway data is not  be 
exported because IP DA is not 
learned via BGP.
7.8.1.0 allows extended gateway 
information in cases where the 
source and destination IP addresses 
are learned by different routing 
protocols, and for cases where is 
source is reachable over ECMP.
BGP
BGP
Exported
Exported
Extended gateway data is packed.