Monday, 1 September 2014

Difference between M-series and F-series card in Nexus 7000.

Cisco Nexus line cards are of two types: - M series and F series.

M card is basically used for L3 purpose like routing etc. whereas F series card was originally a Layer2 card. New third generation of F-series can support L3 features like MPLS, OTV etc.

Below is the list of M-series and F-series cards:-

M-series:-

Few key points

All Cards supports OTV
FCOE and fabricpath not supported in M-series cards.
VPC is supported in all cards.
All M2 series cards and only one M1 cards N7K-M132XP-12L supports FEX whereas other M1 cards don’t support Fex connectivity.
Below are the current M-series cards.

a) M1 cards:-

N7K-M148GS-11L
N7K-M148GT-11L
N7K-M108X2-12L
N7K-M132XP-12L

b) M2 card:-

N7K-M224XP-23L

F series:-

Few key points :

All F-series cards support VPC.
Fex is also supported in all F cards.
FCOE and Fabricpath is also supported in all cards.
OTV, LISP, MPLS is only supported in F3 cards.
M-Series Interoperability in same VDC is only supported with F2e and F3 cards.
Below are the current F-series cards.

a) F1 Card:- F1 card is now end of sale and end of life.

N7K-F132XP-15

b) F2 card:-

N7K-F248XP-25

b) F2e cards:-

N7K-F248XP-25E
N7K-F248XT-25E

c) F3 card:-

N7K-F312FQ-25

There are various model available for not M and F-series and question is can we get any detail by looking at the model number like What is 12 in N7K-M132XP-12L?

Below is the chart which explains the fields in the model number of Line cards. By looking at it you can drive the fields in all available line cards.

Note:

1. There is a separate Fabric in the line card as well. Don't confuse it with the fabric present in the chassis.

2. Number of Fabric card required to support the card can be calculated as:-

Like this card supports 480 Gbps backplane BW, so to get the full BW we need 5 (no. of Fabric cards) *110( BW of each Fbaric card - FAB-2) =550Gbps of fabric speed and hence require 5 fabric card in the chassis.

Nexus Line card Naming Conventions

In the below chart I tried to explain the fields present in the Nexus line card model number. I have taken N7K-F248XT-25E as an example but you can drive the details of any line card using it.

What is GGSN ?

GGSN – Gateway GPSR support Node is the mobility anchor point within the mobile packet core network. It provides connectivity to the SGSN (Serving GPRS support Node) and PDN (Packet data network). Session state information of the subscriber is always maintained at the GGSN. It also maintains the necessary information required to route the user traffic towards the SGSN and PDN.

GGSN is mostly located in the service provider network so even if the subscriber is in roaming location or in the home network, he will be connected to the GGSN located in the home network.

Key functions of GGSN

Process PDP request from SGNSs in both home and foreign PLMN network. After the subscriber is attached to the network, it will initiate the PDP activate procedure.
Assign an IP address to the subscriber - A subscriber could have maximum of 11 PDP context and secondary PDP context. Each subscriber should have at least one primary PDP context in order to access the services with the PRD network. The secondary PDP context would create depending on the type of application the subscriber is accessing. Depending upon the application, the bandwidth requirement may be higher, due to which the secondary PDP context will be created. It depends on the type of application as the application may need more bandwidth which was negotiated in primary PDP context. For every primary PDP context, the GGSN will assign the IP address since the secondary PDP context will be associated with the primary PDP context and therefore GGSN will not assign an IP address to secondary PDP context.
Negotiate QOS – For any given subscriber session the GGSN will negotiate the QOS parameter with SGSN as a part of PDP activation procedure and during any PDP modification procedure.
Dynamic Policy control – GGSN has interface Gx towards the PCRF. This is used for policy control and charging rule function. This function helps the GGSN to charge the subscriber as per the QS policy. Depending upon the type of subscription, PCRF can negotiate various types of QOS policies to the subscriber and install different charging rules.
Performs prepaid / postpaid billing – using the Gy interface GGSN performs the prepaid billing, using the OCS - Online charging server and performs the postpaid billing towards the Charging gateway function.
GGSN also authenticates users to perform the authentication using AAA, OCS and PCRF since all of these maintain a database with the user subscription.
GGSN also provides secure VPN tunnel connectivity of corporate subscriber towards the corporate PDN network. Tunneling mechanism such as GRE, IPSEC, L2TP tunneling can be used for setting up the tunneling interface on the Gi interface.

GGSN interface types –

Gn/Gp interface – Used by GGSN to communicate with SGNSs within the home/PLMN network. This interface is based on the GPRS tunneling protocol (GTP). It uses the GP interface towards the SGSN within the foreign PLMN network. This interface carries both Data and signaling plane traffic for a subscriber PDP session. It uses GTP-C for control signaling and GTP-U for user data traffic.
Gx Interface – It is used to communicate with te PCRF and its bases on the diameter protocol.
Gy Interface – This interface is used between GGSN and OCS. It is based on the diameter protocol used for prepaid billing.
Ga/Gz interface – As per the 3GPP standard, the Gz interface between CTF (charging trigger function) and CDF (charging data function). The CDF is a proxy between GGSN and CGF. The interface between the CDF and CGF is known as Ga interface.
Gi Interface – This interface is between GGSN and PDN. It routes the traffic towards the PDN for the services offered within PDN. This interface carries both uplink and downlink subscriber data.
DHCP interface – This interface goes towards the DHCP server. The GGSN can use this interface if external server is to be used for assigning IP addresses to the subscribers.
GC interface – This interface goes towards HLR via GTP – MAP protocol converter. It is used during network initiated PDP activation procedure.
AAA – This interface goes towards AAA server. It’s based on radius protocol and used for authentication and accounting.

Sunday, 31 August 2014

What is Fabric module in Cisco Nexus 7000 switches ?

Fabric modules provide connectivity between Supervisor module and line cards. 7k chassis support up to 5 fabric cards.

Fabric cards must be present in all 7K nexus switches to make it work except 7004 as it doesn't support fabric card.

Fabric cards are hot swappable, it means we can remove it from the chassis and other Fabric cards will take over with any impact to the traffic.

There are two below types of fabric cards available. the migration from Fab-1 to Fab-2 is non disruptive. But both in the chassis for long duration is not recommended by Cisco.

Fabric module version 1 :-

· 46 Gbps per slot.

· Maximum performance per slot with 5 Fabric modules is 46 * 5 = 230Gbps

· Not supported in 7009 chassis.

· Upto 5 Fabric modules are supported

Fabric module version 2 :-

· 110 Gbps per slot

· Maximum performance per slot with 5 Fabric modules is 110 *5 =550Gbps.

· Supported on all 7K series.

· Upto 5 Fabric modules are supported

Cisco Nexus 7000 Supervisor module comparision - Sup1 Vs Sup2 Vs Sup2E

1. Supervisor 1 :-

Before 6.2, maximum 4 VDC (3 non default + 1 default ) are supported.
In 6.2(2), Sup-1 also support admin VDC. It gives you the option to either create 1 x default VDC and 3 x non default VDC or 1 x admin VDC and 4 x non-default VDC.
Maximum 32 FEX are supported
CMP supported.
CPU – Dula core Xeon
Speed- 1.66 Ghz
Memory – It comes with 4GB RAM and upgrade to 8GB is needed for MPLS and VDC features.
CPU share not supported.

2. Supervisor 2 :-

Maximum 4+1 admin VDC supported. In initial configuration Wizard, we get an option to create admin VDC. If we choose NO, then we can create 1x default VDC and 3 x non default VDC.
Maximum 32 FEX are supported
CMP is not supported.
CPU – Quad core
Speed- 2.13 Ghz
Memory – 8Gb
CPU share is supported

3. Supervisor 2E :-

Maximum 8+ 1 admin VDC supported.
Maximum 64 FEX are supported
CMP is not supported.
CPU – Dual quad core
Speed- 2.13 Ghz
Memory – 32 Gb
CPU share is supported.

Note :-
1. There is a license#LAN_ADVANCED_SERVICES_PKG (N7K-ADV1K9) needed to create more than one VDC upto 4 VDC. Without license you can only use VDC 1 ( admin or default whichever is chosen in the initial wizard).
2. For Sup 2, " VDC Licenses (N7K-VDC1K9) " License is needed to add license for 4 VDCs and hence can support 8 VDCs. Each license increment the vdc number by 4.

2. CPU share is the way by which we can allocate the specific CPU to the important VDCs.

Cisco Nexus 7000 FAQs

1. What are the 7K model available?
Answer:- 7004 , 7009 , 7010 and 7018

2. Is 7004 supports all Fabric Modules?
Answer:- No, Fabric module is not present in 7004 whereas all other Nexus 7K needs fabric module to work.

3. In 7k, Can we use supervisor slot for line cards?
Answer :- No, we cannot use supervisor slots for line card.

4. Is Sup-1 supported in all 7k models?
Answer :- No, Sup-1 is not supported in 7004 whereas all other model supports Sup-1.

5. Is fab-1 supported in all 7K models?
Answer:- No, Fab-1 is not supported in 7004 and 7009.

6. Can we use non-XL M1 model in all 7K?
Answer:- No, non-XL model is not supported in 7004.

7. Can we use mix of Fab-1 and Fab-2 in single chassis?
Answer:- Yes but only one fabric version (1 or 2) is recommended in a chassis.

8. Can we use Fabric module of 7009 to 7018?
Answer: No, we cannot use Fabric module of one model to another.

9. Can we create port-channel with one M-card port and other in F-card port?
Answer:- No, it is not possible to bundle M-series and F-port.

10. Is it possible to create port-channel with M-series on one end an other end is F card?
Answer:- We cannot make port-channel with M port at one end and F at other side.

11. Are FCOE and Fabricpath supported on M-series card?
Answer:- No, Fabricpath and FCOE are not supported on M-series line cards.

12. Is Mixing I/O modules on the same side of a port channel supported?

Answer: No, Mixing of IO modules in a port-channel is not supported.

13. Can we configure LACP on half duplex port?

Answer: - LACP does not support half-duplex mode. Half-duplex ports in LACP port channels are put in the suspended state.

14. Does nexus 7000 series support fragmentation?

Answer:- No, Nexus 7k doesn't support fragmentation and reassembly.

15. Is dense-mode supported on Nexus 7k?

Answer:- No, Nexus 7k only support PIM sparse mode.