Ethernet Switches & Routers

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Occasional Contributor
Posts: 14
Registered: ‎03-31-2011

Sflow on MLX

Just wondering if anyone knows some commands to get layer 3 info from sflow.

Im after a command like cisco's "sh ip cache flow"

Thanks

Super Contributor
Posts: 1,087
Registered: ‎12-13-2009

Re: Sflow on MLX

Hi s.rigby,

NOTE

sFlow is implemented in the default VRF only. Therefore, sFlow data is only accessible by the sFlow collector (sFlow destination host(s)) defined in the default VRF.

The port connected to the collector forwards sFlow packets in the default VRF. Brocade’s implementation of sFlow data collection supports AS path information in the following types of sFlow packet:

* Non-default VRF IPv4 sampled packets

* Non-default VRF IPv6 sampled packets

* Default VRF IPv6 sampled pack

NOTE

Before you enable sFlow, make sure the device has an IP address that sFlow can use as its source address

Enabling sFlow forwarding

To enable sFlow forwarding, enter commands such as the following.

Brocade(config)# sflow enable

Brocade(config)# interface ethernet 1/1 to 1/8

Brocade(config-mif-1/1-1/8)# sflow forwarding

These commands globally enable sFlow, then enable sFlow forwarding on Ethernet ports 1/1 –

1/8. You must use both the sflow enable and sflow forwarding commands to enable the feature.

Syntax: sflow enable

Syntax: sflow forwarding

NOTE

sFlow packets cannot be forwarded from a management interface. You must configure an IP

interface on an Interface module to forward sFlow packets.

Configuration considerations for ACL-based Inbound sFlow

The following sections describe the configuration considerations for ACL-based Inbound sFlow:

• sFlow must be enabled on the router.

• ACL-based mirroring: The mirror and copy-sflow keywords are mutually exclusive on a per ACL clause basis.

• Port-based monitoring: Port-based monitoring and ACL-based sFlow can co-exist on the same interface.

• Port-based sFlow: Port and ACL-based sFlow can co-exist on the same interface. When both features are configured on an interface, packets that qualify as ACL-based sFlow packets are sent to the collector as ACL sample packets. Also, the user can configure ACL-based sFlow on an interface without configuring port-based sFlow.

IP Receive ACLs: IP Receive ACLs are used for filtering or rate-limiting management traffic. The

keyword copy-sflow is also supported for IP Receive ACLs.

• Policy Based Routing: The copy-sflow keyword is applicable for PBR ACLs.

• IPv4 ACL based Rate-Limiting: When the copy-sflow keyword is used in an IPv4 Rate Limiting ACL, only traffic permitted by the Rate Limiting engine is copied to the CPU for forwarding to the sFlow collector.

• IPv4 ACLs on VRF endpoints: You can apply ACL-based sFlow for VRF endpoints however such packets are treated as regular sampled sFlow packets and do not carry proprietary encapsulation. This can create a minor skew of statistics projection.

• L2 ACLs: The copy-sflow keyword is not supported for L2 ACLs.

• If the copy-sflow keyword is used for a clause that is applied to the outbound direction, it is ignored.

Creating an ACL with an sFlow clause

The copy-sflow keyword has been added for inclusion in IPv4 and IPv6 ACL clauses to direct traffic

that meets the criteria in the clause to be sent to the sFlow collector. In the following example, the

ACL is used to direct syn-ack packets sent from a server at address 10.10.10.1.

access-list 151 permit tcp host 10.10.10.1 any established syn copy-sflow

access-list 151 permit any any

The copy-sflow parameter directs selected traffic to the sFlow collector. Traffic can only be selected using the permit clause.

You must apply the ACL to an interface using the ip access-group command as shown in the

following.

Brocade(config)# int eth 1/1

Brocade(config-if-e10000-1/1)# ip access-group 151 in

Specifying an sFlow collector

sFlow exports traffic statistics to an external collector. You can specify up to four collectors. You can specify more than one collector with the same IP address if the UDP port numbers are unique. You can have up to four unique combinations of IP address and UDP port number.

NOTE

sFlow is implemented in the default VRF only. Therefore, sFlow data is only accessible by the sFlow collector (sflow destination host(s)) defined in the default VRF.

To specify sFlow collectors, enter a command such as the following.

Brocade(config)# sflow destination 10.10.10.1

This command specifies a collector with IP address 10.10.10.1, listening for sFlow data on UDP port 6343.

Syntax: sflow destination <ip-addr>

The <ip-addr> parameter specifies the collector’s IP address.

The <dest-udp-port> parameter specifies the UDP port on which the sFlow collector will be listening for exported sFlow data. The default port number is 6343.

Thanks Michael.

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